Respiratory System

These ingredients are often used in alternative medicine to support respiratory system.

• abies spectabilisScientific

  A. spectabilis has preclinically confirmed antitussive, bronchodilatory, and anti-inflammatory activity relevant to the respiratory system. The plant is traditionally central to Himalayan respiratory medicine. The 2021 review confirms multiple in vivo respiratory bioactivities.

• ajwainScientific

  Ajwain has direct human clinical evidence for bronchodilatory activity in asthmatic patients (Boskabady 2007, Therapie). Additional antitussive (guinea pig), tracheal relaxant, and antimicrobial evidence covers multiple respiratory system functions. Traditional use for bronchitis, asthma, and cough is extensive.

• andrographisScientific

  Andrographis paniculata has robust clinical evidence supporting its use for acute upper respiratory tract infections (URTIs). Multiple randomized controlled trials and several systematic reviews and meta-analyses demonstrate that it significantly reduces the severity and duration of URTI symptoms such as sore throat, nasal congestion, headache, and general malaise compared to placebo. Its primary active constituent, andrographolide, exerts anti-inflammatory effects via suppression of the NF-κB signaling pathway, reducing pro-inflammatory cytokine production relevant to respiratory mucosal inflammation. It has also been used traditionally in Ayurvedic and Chinese medicine for coughs, colds, and flu.

• andrographolideScientific

  Andrographolide, the primary bioactive diterpene from Andrographis paniculata, has human clinical evidence supporting its use for acute upper respiratory tract infections (URTIs), with multiple randomized controlled trials and systematic reviews demonstrating symptomatic benefit. Its key mechanism is inhibition of the NF-κB inflammatory pathway. Preclinical data also support potential roles in asthma, COPD, and acute lung injury, though direct human trials for these conditions remain limited.

• anemarrhena asphodeloidesScientific

  Anemarrhena and timosaponin AIII significantly inhibited LPS-induced lung inflammation in animal models, reducing alveolar thickening and cytokine production. Traditional use for fever-related respiratory diseases, bronchitis, cough, and asthma is documented across thousands of years of East Asian clinical practice.

• aniseScientific

  Anise is officially recognized by the ESCOP monograph and EMA for 'catarrh of the upper respiratory tract,' with expectorant and antispasmodic properties. In vitro studies confirmed reduction of bronchial pro-inflammatory cytokines and stimulation of mucus secretion. Animal studies showed bronchodilatory effects of anise extracts and essential oil.

• arabinogalactanScientific

  Human clinical trials demonstrate that larch arabinogalactan supplementation reduces the frequency of upper respiratory infections, the primary clinical manifestation of respiratory system challenge. Its action is immune-mediated—via NK cell activation, macrophage stimulation, and gut-immune axis signaling—rather than through direct respiratory tissue effects. Multiple RCTs and mechanistic reviews substantiate this systemic immune-to-respiratory axis.

• aster rootScientific

  The respiratory system is the primary documented target of Aster root across both traditional and scientific evidence, with over 2,000 years of pharmacopeial documentation and multiple animal studies demonstrating antitussive, expectorant, bronchodilatory, anti-inflammatory, and acute lung injury-protective effects.

• astragalosideScientific

  Astragaloside IV (AS-IV), the primary bioactive saponin of Astragalus membranaceus, has substantial preclinical evidence supporting its role in protecting the respiratory system. It demonstrably suppresses pro-inflammatory cytokines (TNF-α, IL-6, IL-1β), inhibits TGF-β1-driven fibrosis, and attenuates oxidative stress in models of pulmonary fibrosis, COPD, asthma, and acute lung injury. Human clinical evidence remains limited; safety trials confirm tolerability of IV administration, but efficacy in lung disease has not yet been established in large-scale human RCTs.

• astragalusScientific

  Astragalus membranaceus (Huangqi) has documented clinical and preclinical evidence supporting its use in multiple respiratory conditions, including upper respiratory tract infections (URTIs), asthma, COPD, and pulmonary fibrosis. Its principal bioactive constituents—polysaccharides, astragalosides (notably astragaloside IV), and flavonoids—confer anti-inflammatory, immunomodulatory, antioxidant, and anti-fibrotic mechanisms relevant to respiratory pathology. Human clinical trials and meta-analyses exist, though most are limited by small sample sizes and methodological constraints. NCCIH notes there is not yet sufficient reliable evidence to confirm efficacy for any respiratory indication definitively.

• bacillus clausiiScientific

  Pilot clinical evidence shows B. clausii reduces the frequency and duration of recurrent respiratory infections in children through the gut-lung immune axis. It modulates cytokine profiles in nasal mucosa in patients with allergic rhinitis in both children and adults. Evidence is preliminary and based on small pilot RCTs.

• baicalinScientific

  Baicalin, a flavonoid from Scutellaria baicalensis (Huang Qin), has extensive preclinical evidence supporting its role in respiratory health, including anti-inflammatory, antioxidant, antiviral, and immunomodulatory effects studied across conditions such as COPD, acute lung injury, asthma, pulmonary fibrosis, and viral respiratory infections. Its parent herb has been used in Traditional Chinese Medicine for over 2,000 years specifically for lung problems. The current body of evidence is predominantly in vitro and animal-model based; robust human clinical trials remain limited, meaning the scientific classification reflects documented pharmacological activity rather than confirmed clinical efficacy in humans.

• baikal skullcapScientific

  S. baicalensis is used clinically in China for upper respiratory infections, pneumonia, bronchitis, and asthma. Baicalin demonstrates in vitro and in vivo antiviral activity against RSV, influenza H1N1/H3N2, and shows anti-inflammatory, antibacterial, and anti-allergic effects in the respiratory context.

• barrenwortScientific

  A comprehensive 2025 narrative review in ScienceDirect evaluated Epimedium and its bioactive compounds for respiratory diseases, confirming anti-inflammatory, antioxidant, and immunomodulatory activities relevant to asthma, COPD, pulmonary fibrosis, and other conditions. Traditional Chinese medicine has used Epimedium for bronchitis and asthma for centuries.

• basilScientific

  O. basilicum has the most extensively reviewed respiratory evidence of any system, including animal RCT data for asthma, documented bronchodilatory properties (linalool metabolites), and traditional use for asthma, bronchitis, cough, and sore throat across multiple countries. A Frontiers in Pharmacology systematic review (2021) covers preclinical, experimental, and clinical respiratory evidence.

• belleric myrobalanScientific

  T. bellirica has pharmacologically validated bronchodilatory and antispasmodic effects on the respiratory system (Gilani et al., J Ethnopharmacol 2008), demonstrating anticholinergic and calcium channel antagonist mechanisms. Traditional use for asthma, bronchitis, cough, sore throat, and respiratory tract infections is among the herb's most consistent documented applications across Ayurveda, Unani, Siddha, and Chinese medicine.

• beta-caroteneScientific

  Beta-carotene has a scientifically critical and complex relationship with the respiratory system: early epidemiological studies suggested dietary beta-carotene was inversely associated with lung cancer risk, but landmark RCTs (ATBC and CARET) demonstrated that high-dose supplementation (20–30 mg/day) paradoxically increased lung cancer incidence by 18–28% and total mortality in smokers and asbestos-exposed individuals. Food-based beta-carotene intake has not been shown to increase lung cancer risk.

• beta-glucanScientific

  Beta-glucan's immunomodulatory effects have demonstrated clinical benefit in reducing upper respiratory tract infection (URI) incidence and duration, and in alleviating respiratory allergic symptoms. Oral beta-glucan stabilizes secretory IgA at mucosal surfaces. Both URI prevention and allergic rhinitis symptom reduction have been demonstrated in RCTs.

• bifidobacterium lactisScientific

  B. lactis strains modulate respiratory system health via the gut-lung axis, reducing allergic airway inflammation (IgE, IL-13, Th2 cytokines) and lowering susceptibility to viral URTIs. Multiple RCTs in adults and children support reduced URTI risk and reduced allergic rhinitis symptoms.

• black cuminScientific

  Multiple clinical studies and reviews confirm N. sativa has bronchodilatory, anti-inflammatory, and preventive effects across asthma, allergic rhinitis, COPD, and other respiratory disorders. Clinical trials show significant improvement in asthma symptoms and pulmonary function tests with 1–2 g/day seeds for 3–12 weeks.

• blackboard treeScientific

  A. scholaris leaf alkaloids have demonstrated antitussive, antiasthmatic, and expectorant activities in multiple animal models, supported by PubMed-indexed studies. Traditional use across Asian and African systems for asthma, bronchitis, and cough is well-documented.

• borageScientific

  Borage seed oil GLA has scientific evidence for respiratory benefit across two contexts: bronchial asthma (Phase 2 RCT showing significant clinical improvement) and acute respiratory distress syndrome (ARDS), where EPA+GLA enteral formulas reduced ventilator days and ICU stay in a multi-centre RCT. Traditional use additionally covers bronchitis, pleurisy, and colds.

• borage oilScientific

  Enteral nutrition with EPA (fish oil), GLA (borage oil), and antioxidants has been evaluated in multiple RCTs for ARDS/ALI; a landmark multicenter double-blind RCT (n=146) found this formula reduced pulmonary neutrophil recruitment, improved oxygenation, reduced ventilator days (11 vs. 16.3 days), and decreased ICU length of stay. GLA also suppresses airway leukotriene production relevant to asthma.

• boswelliaScientific

  Boswellia serrata has human clinical trial evidence supporting its use for bronchial asthma, primarily through inhibition of the 5-lipoxygenase (5-LOX) enzyme and consequent reduction in leukotriene synthesis, which drives airway inflammation and bronchoconstriction. The landmark published trial (Gupta et al., Eur J Med Res, 1998) found 70% of treated patients showed measurable improvement versus 27% on placebo. A 2018 placebo-controlled trial of a Boswellia-containing combination further confirmed significant improvements in asthma symptom scores and cytokine balance. However, the overall body of evidence remains limited by small sample sizes, and regulatory bodies such as NCCIH note that rigorous evidence is still insufficient to establish Boswellia as a definitive asthma treatment.

• boswellic acidScientific

  Boswellic acids, derived from Boswellia serrata gum resin, have demonstrated respiratory benefits primarily through inhibition of 5-lipoxygenase (5-LOX), which suppresses leukotriene synthesis central to bronchoconstriction and airway inflammation. At least one double-blind, placebo-controlled clinical trial in bronchial asthma patients showed significant improvements in pulmonary function and symptom reduction. Evidence is characterized as preliminary but mechanistically plausible, with clinical studies limited by small sample sizes and short durations.

• bromelainScientific

  Bromelain has mucolytic properties and anti-inflammatory effects documented in upper and lower respiratory conditions including sinusitis, bronchitis, COPD, and allergic airway disease. Clinical studies in sinusitis show reduced nasal inflammation and improved mucosal outcomes. Animal models confirm attenuation of allergic airway inflammation with altered T lymphocyte populations.

• butterburScientific

  Butterbur (Petasites hybridus) has human clinical trial evidence supporting its use in allergic rhinitis and asthma, two key respiratory conditions. Its active sesquiterpenes—petasin and isopetasin—inhibit leukotriene biosynthesis and histamine H1 receptors, dampening airway inflammation. A landmark RCT found butterbur extract comparable in efficacy to the antihistamine cetirizine for seasonal allergic rhinitis. Evidence in asthma is more limited, with only small or open trials; one placebo-controlled crossover study in 16 asthmatic patients showed improved bronchial hyperresponsiveness, and a larger open trial reported reduced attack frequency and improved lung function.

• caffeineScientific

  Caffeine is a weak bronchodilator and reduces respiratory muscle fatigue, acting as a weak methylxanthine structurally related to the asthma drug theophylline. Cochrane-reviewed evidence confirms it improves lung function in asthma patients for up to four hours. Its bronchodilatory effect is significant enough to confound spirometry results.

• cajuputScientific

  Cajuput oil has extensive traditional and pharmacological evidence for its respiratory effects, primarily through its 1,8-cineole content acting as an expectorant, mucolytic, and nasal decongestant via TRPM8 receptor activation. It is a licensed active ingredient in OTC respiratory products (Olbas Oil). Clinical studies on isolated 1,8-cineole (found in cajuput) show benefit in rhinosinusitis, asthma, and COPD in RCTs.

• camphor oilScientific

  Camphor oil is a recognized active ingredient in OTC chest rubs and nasal decongestant products for respiratory symptom relief. The PMC 2023 bibliometric review identified URI symptom management as a primary clinical topic. Camphor and menthol activate TRP channel M8, inhibiting cough reflexes and creating the sensation of easier breathing.

• capsaicinoidsScientific

  Capsaicin has been clinically trialed for rhinitis, nasal polyposis, chronic cough, and sinusitis. Intranasal capsaicin demonstrates efficacy for idiopathic rhinitis in double-blind RCTs. A 2022 scoping review confirms capsaicin has been trialed in multiple respiratory conditions with documented safety.

• capsicumScientific

  Capsaicin acts on TRPV1 receptors in the respiratory mucosa, with established clinical use in intranasal capsaicin for non-allergic rhinitis (supported by Cochrane review) and emerging data on airway desensitization. Animal studies support anti-fibrotic pulmonary effects via Nrf2/PPAR-γ and NF-κB modulation.

• caroteneScientific

  Vitamin A from beta-carotene is essential for maintaining respiratory epithelial integrity and mucosal immune defense. Deficiency impairs lung development and maturation, increases susceptibility to respiratory infection, and is associated with abnormal lung function. High-dose supplemental beta-carotene paradoxically increased lung cancer risk in smokers in two landmark RCTs.

• cayenne pepperScientific

  Intranasal capsaicin is supported by Cochrane-reviewed evidence for idiopathic non-allergic rhinitis (4 studies, n=302). Capsaicin acts on TRPV1 receptors in respiratory mucosa, modulating neurogenic secretion and hypersensitivity. Traditional use for bronchitis, congestion, and cough is extensively documented.

• chaff flowerScientific

  A. aspera has documented bronchodilator activity in a PubMed-indexed ex vivo and in vivo study, and traditional use for asthma, bronchitis, cough, and phlegm is extensive across South Asian and African systems.

• chlorellaScientific

  A clinical RCT in 97 COPD and asthma patients showed chlorella extract significantly improved antioxidant enzyme status (SOD, CAT, GPx, glutathione, vitamins C and E) as adjunctive therapy, though spirometric parameters did not significantly improve. Animal research also supports anti-inflammatory effects in a COPD model.

• chrysinScientific

  In an OVA-induced chronic asthma mouse model, chrysin reduced eosinophil counts, Th2 cytokines (IL-4, IL-13), total IgE, goblet cell hyperplasia, and α-SMA expression, while inhibiting airway smooth muscle cell proliferation via Akt/ERK pathway suppression. Results indicate potential against both airway inflammation and remodeling.

• chymotrypsinScientific

  Alpha-chymotrypsin is used as a mucolytic agent in the respiratory system, directly liquefying mucus and decreasing sputum viscosity. It has been administered by inhalation and intrabronchial instillation. A 2021 PMC case report documented successful chymotrypsin instillation to dissolve obstructive bronchial casts.

• cineoleScientific

  1,8-cineole (eucalyptol) has robust clinical evidence supporting its use in respiratory conditions including COPD, asthma, acute bronchitis, and rhinosinusitis. Multiple placebo-controlled, double-blind trials demonstrate mucolytic, bronchodilating, and anti-inflammatory effects. Its mechanisms include inhibition of cytokine release, suppression of arachidonic acid metabolism, and increased ciliary beat frequency in the airway mucosa.

• CLA (conjugated linoleic acid)Scientific

  CLA has been studied for effects on airway inflammation in asthma. A clinical trial found 4.5 g/day CLA improved airway hyper-responsiveness in overweight mild asthmatics. A pediatric RCT found modest cellular anti-inflammatory effects but no improvement in clinical asthma symptoms.

• cod liver oilScientific

  Vitamin D from cod liver oil activates innate immune pathways in airways, reducing respiratory infection susceptibility. Vitamin A maintains mucosal epithelial integrity in bronchial airways. The HUNT observational study found CLO intake associated with lower adult asthma incidence. EPA and DHA reduce airway inflammatory mediators.

• coleus forskohliiScientific

  Coleus forskohlii, via its active compound forskolin, has documented clinical use for asthma and respiratory disorders. Forskolin elevates intracellular cAMP, causing bronchial smooth muscle relaxation and suppression of inflammatory mediators. Two published single-blind clinical trials in asthma patients demonstrate reduced attack frequency with oral forskolin. Evidence, while promising, remains limited by small sample sizes and single-blind designs.

• colostrumScientific

  Bovine colostrum supports respiratory mucosal immunity via secretory IgA and immunoglobulins that protect mucosal surfaces against pathogens. Clinical meta-analysis shows a 44% reduction in URTI symptomatic days in exercising adults. Both athletes and high-risk non-athletic populations (medical students) have demonstrated benefit.

• cordycepsScientific

  Cordyceps (primarily C. sinensis and C. militaris) has documented human clinical evidence supporting its use for respiratory conditions, particularly COPD and asthma. A 2019 systematic review and meta-analysis of 15 RCTs (1,238 participants) found benefits in lung function, exercise endurance, quality of life, and symptom improvement in stable COPD patients. Traditional Chinese medicine has used Cordyceps to 'tonify the lung' and treat chronic cough for centuries, and this use is now backed by a growing body of preclinical and clinical data. Evidence quality varies, with methodological limitations noted in several trials.

• curcuminScientific

  Curcumin has been evaluated in human clinical trials for several respiratory conditions, including asthma, COPD, and chemical-induced pulmonary injury. Its primary mechanisms are suppression of NF-κB-driven airway inflammation and reduction of oxidative stress. A meta-analysis of asthma trials found a modest but statistically significant improvement in FEV1%, though evidence remains limited by small sample sizes and methodological heterogeneity. Overall, clinical evidence is emerging but not yet conclusive.

• d-alpha tocopherolScientific

  Alpha-tocopherol specifically modulates lung inflammation through its unique antagonism of PKCα, inhibiting allergic airway inflammation in both clinical trials and animal studies. This isoform-specific activity distinguishes it from gamma-tocopherol, which promotes lung inflammation, making d-alpha tocopherol the preferred form for respiratory health.

• DHA (docosahexaenoic acid)Scientific

  Higher circulating DHA levels are associated with attenuated lung function decline, lower incidence of airway obstruction, and reduced COPD morbidity in large longitudinal and Mendelian randomization studies. Epidemiological data also link DHA intake to reduced asthma onset risk. Clinical intervention data are still emerging, but the association is consistent across diverse populations.

• diamine oxidaseScientific

  DAO deficiency permits excess histamine to reach the respiratory mucosa, causing symptoms including rhinorrhea, nasal obstruction, bronchospasm, cough, and sinusitis. Clinical evidence documents reduced nasal airflow in allergic rhinitis patients with low DAO, and DAO supplementation significantly reduces respiratory symptom scores in HIT trials.

• echinaceaScientific

  Echinacea has substantial clinical evidence supporting its use for upper respiratory tract infections (URTIs), including the common cold. Multiple meta-analyses of randomized controlled trials show statistically significant reductions in URTI incidence and complications, though evidence on shortening illness duration is mixed. The active constituents — alkylamides, polysaccharides, and caffeic acid derivatives — modulate innate immune responses via macrophage activation and cytokine regulation. Methodological heterogeneity across trials limits the certainty of conclusions.

• echinacea purpureaScientific

  Echinacea purpurea has been evaluated in multiple randomized controlled trials and systematic reviews for the prevention and treatment of upper respiratory tract infections (URTIs). Its key bioactive compounds — alkamides, caffeic acid derivatives (notably chicoric acid), flavonoids, and polysaccharides — are understood to modulate innate immunity and exert direct antiviral activity against enveloped respiratory viruses. Meta-analytic evidence from both adult and pediatric populations supports reductions in URTI incidence, symptom duration, and antibiotic use, though heterogeneity across preparations and methodological variability temper the strength of conclusions.

• EGCG (epigallocatechin gallate)Scientific

  EGCG attenuates cigarette smoke-induced airway neutrophilic inflammation, mucus hypersecretion, and collagen deposition in rat models. It also protects against LPS-induced acute lung injury and PM2.5-triggered lung inflammation, and exhibits antimicrobial properties against pulmonary pathogens.

• elderberryScientific

  Multiple randomized controlled trials and meta-analyses support elderberry (Sambucus nigra) for reducing the duration and severity of upper respiratory symptoms, particularly influenza and the common cold. A 2019 meta-analysis of RCTs found a large effect size for symptom reduction, and a 2021 systematic review (5 RCTs) confirmed possible benefits for cold and flu duration. NIH/NCCIH acknowledges this preliminary clinical evidence, though overall certainty remains uncertain due to small trial sizes.

• eleutheroScientific

  Eleuthero has documented effects on respiratory health through both immunomodulation and direct antiviral activity. Large clinical trials in Russia demonstrated reduced respiratory illness rates and fewer influenza complications. Children and adults supplemented with eleuthero showed markedly lower morbidity from respiratory viral infections.

• ephedraScientific

  Ephedra (Ma Huang) has well-documented effects on the respiratory system, primarily through its alkaloids ephedrine and pseudoephedrine, which act as sympathomimetic bronchodilators. Clinical evidence, including double-blind trials in asthmatic patients, confirms ephedrine's bronchodilatory efficacy. Major institutional sources (Cleveland Clinic, Memorial Sloan Kettering) identify short-term treatment of asthma, bronchitis, and bronchospasm as the most convincingly supported use of ephedra. This scientific evidence is layered on top of more than 5,000 years of Traditional Chinese Medicine (TCM) use for cough, asthma, and respiratory congestion.

• eucalyptusScientific

  Eucalyptus—primarily via its major constituent 1,8-cineole (eucalyptol)—has substantial human clinical evidence supporting its use for respiratory conditions including asthma, COPD, acute bronchitis, and rhinosinusitis. Its principal mechanisms are mucolytic, anti-inflammatory (via NF-κB and arachidonic acid pathway suppression), bronchodilatory, and antimicrobial. Multiple randomized controlled trials and a systematic review of RCTs underpin this relationship, though effect sizes are generally moderate and further large-scale trials are still called for.

• european elderScientific

  European elder is one of the most documented botanicals for respiratory system support, with RCT evidence for reducing duration and severity of viral respiratory illness. EMA, German Commission E, and WHO monographs formally recognize elderflower for respiratory conditions. The antiviral and anti-inflammatory mechanisms are well characterized.

• fish oilScientific

  Fish oil omega-3s have anti-inflammatory properties relevant to respiratory conditions including asthma, COPD, and acute respiratory distress. EPA and DHA generate pro-resolving mediators and activate Nrf2 antioxidant pathways in bronchial epithelial cells. Dietary fish oil has been shown to alleviate symptoms and improve lung function in animal models of COPD, asthma, and ARDS, with some supporting human clinical evidence.

• forskohlii rootScientific

  Forskolin bronchodilates by raising cAMP in airway smooth muscle, inhibiting mast cell degranulation, and reducing leukotriene release. Small human RCTs show reduction in asthma attacks with oral dose and bronchodilation with inhaled/IV forms. Ayurvedic tradition strongly links C. forskohlii to respiratory care.

• forskolinScientific

  Forskolin, a diterpene from Coleus forskohlii root, has demonstrated bronchodilatory activity in animal studies and small human clinical trials, primarily in the context of asthma. Its mechanism—direct activation of adenylate cyclase to raise cyclic AMP in airway smooth muscle—is well-characterized. Clinical evidence is limited to small, single-blind trials with mixed lung-function outcomes, though attack-frequency reduction has been reported.

• forsythiaScientific

  Forsythia suspensa is a cornerstone TCM herb for the respiratory system, acting on the lung meridian. It has substantial preclinical evidence for protection against acute lung injury, viral pneumonia (RSV, influenza), bronchiolitis, and pulmonary fibrosis. Combination formulas have documented clinical use in China for respiratory infections including COVID-19.

• fritillaryScientific

  The respiratory system is the primary pharmacological target of fritillary across all major species and all major reviews. Antitussive, expectorant, bronchodilatory, anti-asthmatic, anti-inflammatory, and anti-fibrotic actions in the respiratory system are documented across numerous preclinical studies and supported by clinical TCM use.

• gamma tocopherolScientific

  Multiple human RCTs and controlled studies demonstrate that γT-enriched supplementation reduces eosinophilic and neutrophilic airway inflammation in asthma patients and healthy volunteers exposed to endotoxin, ozone, and wood smoke. Mechanistic actions include RNS scavenging in the airway lumen and COX-2 inhibition.

• garlicScientific

  Garlic (Allium sativum) has documented human clinical evidence supporting its role in reducing the incidence and burden of upper respiratory tract infections, primarily through the antimicrobial, antiviral, anti-inflammatory, and immunomodulatory properties of its organosulfur compounds, especially allicin. A Cochrane systematic review identified one qualifying RCT showing markedly fewer cold episodes in garlic users versus placebo. Additional RCTs and a PMC-published clinical study in elderly volunteers further support reduced infection incidence and symptom duration. Preclinical and mechanistic research also suggests relevance to asthma, COPD, and bacterial lung pathogens, though human trial data for those conditions remain limited.

• garlic bulbScientific

  Garlic's allicin demonstrates in vitro antimicrobial activity against major respiratory pathogens including Streptococcus pneumoniae, Pseudomonas aeruginosa, and MDR Staphylococcus as a volatile agent. Traditional use for respiratory ailments is documented across Chinese, Japanese, Ayurvedic, and North American indigenous medicine systems.

• gentian rootScientific

  The ESCOP monograph for gentian root cites in vivo animal data showing elevation of bronchosecretion (mucus secretion in airways), providing a pharmacological basis for respiratory mucosal effects. Gentian is a component of Sinupret, clinically studied for sinusitis, implicating upper respiratory tract benefit. The bitter taste receptors (TAS2R) are also expressed in tracheal cells and throughout the respiratory mucosa.

• geraniumScientific

  Pelargonium (particularly P. sidoides EPs 7630) has the strongest clinical evidence base among herbal remedies for respiratory infections, including a Cochrane review and EMA approval. P. graveolens has traditional use and emerging ACE2-inhibitory in vitro evidence for respiratory viral infections.

• gingerScientific

  Ginger (Zingiber officinale) has well-documented laboratory and preclinical evidence supporting bronchodilatory and anti-inflammatory effects on the respiratory system, primarily via its active constituents 6-gingerol, 8-gingerol, and 6-shogaol. These compounds relax airway smooth muscle (ASM), inhibit pro-inflammatory mediators (NF-κB, COX-1/2, 5-lipoxygenase), and reduce pulmonary eosinophil recruitment in animal models. Fresh ginger has also demonstrated antiviral activity against human respiratory syncytial virus (HRSV) in airway epithelial cell lines. Clinical human trial evidence remains limited and mixed, with the strongest RCT data showing only modest benefits for acute respiratory infections and COVID-19.

• ginsengScientific

  Multiple randomized controlled trials and systematic reviews support ginseng's role in reducing the frequency, severity, and duration of acute respiratory tract infections, primarily through immunomodulation. A 2025 meta-analysis found ginseng reduced acute respiratory illness risk by over 40% and accelerated recovery by ~3.4 days versus placebo. Evidence for chronic conditions like COPD is mixed, with a rigorous 12-month RCT (n=168) finding no significant benefit over placebo for quality of life or exacerbation rate. Traditional use in Chinese medicine for respiratory symptoms spans thousands of years and predates the clinical evidence.

• ginsenosidesScientific

  Ginsenosides have demonstrated scientifically documented activity across multiple respiratory conditions, supported by preclinical mechanistic data and some human clinical evidence. Key ginsenosides (Rb1, Rg1, Rg3, Rh2) suppress airway and lung inflammation via NF-κB, MAPK, Nrf2, and PI3K/Akt pathways. A meta-analysis of 23 RCTs (1,804 COPD patients) found that Shengmai injection—containing ginsenosides Re, Rg1, and Rb1—significantly improved pulmonary function and clinical outcomes as an adjunct to standard care. Evidence base is strongest in preclinical models; robust standalone clinical trials for isolated ginsenosides remain limited.

• glehnia littoralisScientific

  G. littoralis is one of TCM's primary respiratory herbs, formally listed in the Chinese Pharmacopoeia. Documented uses include chronic bronchitis, cough, lung heat, and asthma. Preclinical antitussive and anti-inflammatory data support these applications, with clinical TCM use providing additional documentation.

• glycyrrhizinScientific

  Glycyrrhizin, the primary bioactive triterpene from licorice root (Glycyrrhiza glabra), has documented antiviral, anti-inflammatory, and immunomodulatory activities relevant to the respiratory system. Human clinical trials — including a randomized double-blind trial in upper respiratory tract infection patients and a randomized controlled trial of nebulized glycyrrhizin in COVID-19 — demonstrate measurable benefits such as shortened hospitalization and modulation of pro-inflammatory cytokines. Preclinical evidence further supports protection against acute lung injury and ARDS via inhibition of the NLRP3 inflammasome and HMGB1/NF-κB signaling pathways. Human clinical evidence exists but remains limited in scale and scope, warranting larger confirmatory trials.

• green chirettaScientific

  Green chiretta has the strongest and most extensively replicated clinical evidence base of any botanical for the respiratory system, specifically for acute respiratory tract infections. Systematic reviews, meta-analyses, and over 33 RCTs confirm benefits across cough, sore throat, nasal congestion, and fever in URTI.

• green-lipped musselScientific

  The primary respiratory evidence for GLM derives from the Emelyanov et al. (Eur Respir J, 2002) double-blind RCT, in which GLM lipid extract significantly reduced airway inflammation markers (exhaled H2O2), improved morning peak expiratory flow, and reduced daytime wheezing in 46 patients with steroid-naïve atopic asthma over 8 weeks. The mechanism is inhibition of leukotriene synthesis via 5-LOX pathway blockade, reducing the key mediators of bronchial inflammation.

• hedychium spicatumScientific

  The respiratory system is the most scientifically supported body system for H. spicatum. Preclinical studies confirm bronchodilator, antihistaminic, anti-asthmatic, and anti-inflammatory activity in respiratory models. Ayurvedic medicine classifies it in 'Shwasahara mahakashaya'—herbs with direct action on respiratory disease.

• hesperidinScientific

  Hesperidin has documented activity against airway inflammation across multiple respiratory conditions including asthma, COPD, pulmonary fibrosis, and ARDS. It inhibits NF-κB, iNOS, COX-2, and pro-inflammatory cytokines in lung tissue and activates the ERK/Nrf2 antioxidant pathway. Evidence is currently preclinical; human respiratory RCTs have not been published.

• honeyScientific

  The strongest clinical evidence for honey concerns its respiratory effects: multiple RCTs and two Cochrane systematic reviews confirm honey reduces cough frequency and severity in children with URTIs and is superior to placebo, salbutamol, and antihistamines. A 2021 BMJ Evidence-Based Medicine meta-analysis confirmed honey's benefit for adult URTI symptoms as well.

• honeysuckleScientific

  Honeysuckle (Lonicera japonica), known in TCM as Jin Yin Hua, has a long history of traditional use for respiratory conditions including coughs, fever, sore throat, and upper respiratory infections. Modern laboratory and clinical research supports antiviral, anti-inflammatory, and immunomodulatory mechanisms relevant to the respiratory system. Clinical evidence is primarily derived from multi-herb formulas containing honeysuckle (notably Shuanghuanglian), with isolated honeysuckle human trials remaining limited; larger, high-quality trials are still needed.

• horseradishScientific

  There is robust clinical and preclinical evidence for horseradish's effects on the respiratory system. Clinical studies of the Angocin combination product show efficacy for acute sinusitis, bronchitis, and upper RTI. The German Commission E endorses external use for respiratory congestion. Isothiocyanates are excreted via the respiratory tract, providing local antimicrobial activity.

• hyssopScientific

  Hyssop's primary clinical and traditional affinity is the respiratory system. A randomized controlled trial supports efficacy in asthma. Traditional use for coughs, bronchitis, congestion, and upper respiratory illness is documented across multiple classical medicine systems. Antispasmodic, expectorant, anti-inflammatory, and antiviral mechanisms are relevant.

• indian baelScientific

  A placebo-controlled double-blind clinical study with a bael-containing herbal combination showed significant alleviation of asthma symptoms. Traditional Ayurveda documents bael for asthma, acute bronchitis, and upper respiratory tract infections. Anti-inflammatory mechanisms provide pharmacological plausibility.

• indian frankincenseScientific

  Clinical RCTs demonstrate Boswellia serrata's efficacy in the respiratory system primarily via the asthma trial (Gupta et al., 1998), showing 70% improvement in FEV1, FVC, PEFR, and reduced attacks vs. 27% placebo response. Leukotriene inhibition by boswellic acids provides the mechanism for bronchial anti-inflammatory effects.

• indian tinosporaScientific

  The most robust human clinical evidence for T. cordifolia concerns the upper respiratory system, specifically the allergic rhinitis RCT (Badar et al., 2005). Traditional use spans lower respiratory conditions including asthma and cough. The COVID-19 trial also enrolled patients with respiratory symptoms. Anti-inflammatory and immunomodulatory mechanisms underpin respiratory effects.

• inula racemosaScientific

  I. racemosa has preclinical scientific evidence for multiple respiratory system effects including bronchodilation, mast cell stabilization, antihistamine activity, anti-inflammatory action, and expectorant properties. These are supported by animal studies and mechanistic in vitro data, alongside deep traditional documentation across multiple medicine systems.

• ivyScientific

  Ivy leaf (Hedera helix) has substantial human clinical evidence supporting its use for respiratory conditions, particularly acute bronchitis and cough associated with upper respiratory tract infections. The active saponins—principally hederacoside C, metabolized to α-hederin—exert expectorant, secretolytic, and bronchospasmolytic effects via indirect β2-adrenergic receptor upregulation. Multiple controlled trials and large observational studies demonstrate symptomatic improvement, though overall evidence quality is moderate and some reviews note methodological limitations.

• L-cysteineScientific

  L-cysteine (as NAC) is one of the most widely studied and clinically applied agents for respiratory system health. Its mucolytic, antioxidant, anti-inflammatory, and anti-biofilm properties make it a standard adjunct therapy for COPD, bronchiectasis, cystic fibrosis, and chronic bronchitis. A 2026 expert consensus confirmed its broad clinical utility across chronic respiratory diseases.

• L-cystineScientific

  L-cystine's metabolic conversion to cysteine underpins the respiratory system relevance of the cysteine family: cysteine provides the sulfhydryl group that cleaves mucin disulfide bonds (mucolytic action) and is the rate-limiting precursor for glutathione, which protects airway epithelial cells from oxidative and inflammatory damage. This is the biochemical basis for NAC's approved respiratory indications.

• L-glutathioneScientific

  Glutathione is the principal antioxidant in the airway epithelial lining fluid and is central to respiratory defense. GSH depletion characterizes COPD, asthma, and other lung disorders. Sublingual and inhaled GSH supplementation approaches have been clinically studied with mixed results; nebulized GSH paradoxically causes bronchoconstriction in asthma.

• lactobacillus caseiScientific

  L. casei Shirota and L. casei DN-114001 have been studied in RCTs specifically for reducing respiratory infections in adults, elderly, and children. Daily fermented milk with L. casei Shirota reduced URTI incidence and duration in office workers. L. casei DN-114001 reduced respiratory infection duration in elderly subjects. An adjunct trial in childhood fast-breathing pneumonia also demonstrated benefit.

• lactobacillus paracaseiScientific

  L. paracasei is among the most studied probiotics for respiratory health, with evidence spanning allergic airway inflammation, upper respiratory tract infections, asthma, and influenza. RCTs demonstrate reductions in URTI frequency and severity, improved asthma control in children, and mitigation of allergic rhinitis symptoms. The gut-lung immune axis is the primary mechanistic pathway.

• lactobacillus rhamnosusScientific

  L. rhamnosus reduces incidence and severity of upper and lower respiratory tract infections in multiple RCTs and supports immune modulation relevant to asthma and allergic rhinitis. A 571-child RCT showed 17% reduction in respiratory infections with complications. In vitro data show direct antiviral effects in nasal epithelial cells against RSV.

• lactobacillus salivariusScientific

  L. salivarius has clinical relevance to the respiratory system through the gut-lung axis, with RCT evidence in pediatric asthma (PROPAM study) and clinical data on upper respiratory infection prevention. L. salivarius LS01 with B. breve B632 reduced asthma exacerbation frequency and severity in children, and strain PS7 has been developed for AOM and upper respiratory infection prevention.

• lactoferrinScientific

  Lactoferrin is a natural component of bronchial secretions and has been clinically studied for respiratory tract infection prevention with positive findings in selected populations. A systematic review and meta-analysis of 25 human studies found significant immune function improvement, with RTI-specific outcomes included in multiple trials.

• lactoperoxidaseScientific

  Lactoperoxidase is a natural constituent of airway surface liquid secreted by bronchial and nasal mucosal glands. It contributes to the innate antimicrobial defense of the respiratory epithelium through the DUOX/LPO/thiocyanate axis. Ex vivo studies using human bronchial epithelial cells demonstrate its capacity to inactivate respiratory bacteria and influenza viruses via hypothiocyanite production.

• licorice rootScientific

  Licorice root has millennia of documented use for respiratory complaints and is recognized by the WHO, German Commission E, and Health Canada as a demulcent and expectorant for coughs, bronchitis, and upper respiratory catarrh. Its key bioactive compounds—glycyrrhizin, liquiritin, and liquiritin apioside—have demonstrated antitussive, expectorant, anti-inflammatory, and antiviral activities in preclinical and some human studies. NCCIH notes that human clinical evidence remains limited in quality and volume, so the overall evidence base is best characterized as mixed: strong traditional/regulatory recognition with emerging but not yet robust clinical trial data.

• limoneneScientific

  Limonene demonstrates anti-inflammatory effects in the respiratory system through suppression of Th2 cytokines, IgE, and inflammatory cells in asthma models, and attenuation of acute lung injury via cytokine inhibition. A systematic review found it effective in preventing and controlling respiratory system injuries. Evidence is preclinical and mechanistic.

• luteolinScientific

  Luteolin has been systematically reviewed for protective effects across the entire respiratory system, covering pneumonia, ALI/ARDS, asthma, COPD, and pulmonary fibrosis through multiple anti-inflammatory and antioxidant signaling mechanisms.

• malabar nutScientific

  Adhatoda vasica's primary clinical relevance is the respiratory system, with bronchodilatory, expectorant, antitussive, and mucoprotective activities confirmed across in vitro, animal, and clinical studies. Two published RCTs support its role in respiratory symptom management.

• marshmallowScientific

  Marshmallow root (Althaea officinalis) has both a deep traditional history and meaningful clinical/scientific evidence supporting its use for respiratory complaints, particularly dry, irritative cough and oropharyngeal mucosa irritation. Its primary active constituents are mucilage polysaccharides, which form a protective film over inflamed respiratory mucosa. Controlled clinical studies and regulatory monographs from ESCOP and the EMA confirm antitussive effects in adults and children. Evidence quality is modest—mostly observational and small controlled studies—but is sufficient for formal traditional-use registration in several EU countries.

• menthol oilScientific

  Menthol has documented effects on respiratory sensory pathways, improving subjective nasal airflow sensation in congestion and suppressing cough reflex via TRPM8 activation. It is an active ingredient in FDA-regulated OTC cough and cold products.

• mintScientific

  Menthol in peppermint oil is a pharmacologically active component in respiratory products, stimulating nasal TRPM8 receptors to produce subjective decongestion. The German Commission E approved peppermint for respiratory catarrhs. In vitro evidence supports antimicrobial activity against respiratory pathogens. Objective airway resistance effects are minimal.

• monk fruitScientific

  Monk fruit has extensive, well-documented traditional use for respiratory complaints including cough, sore throat, and phlegm in TCM, supported by centuries of practice. This traditional use is buttressed at the clinical level by the Tan et al. (2019) RCT demonstrating efficacy of luo han guo decoction for post-intubation throat and respiratory discomfort. Preclinical data on anti-inflammatory and antitussive properties of mogrosides provide mechanistic plausibility.

• mucinScientific

  Mucins are the major structural components of airway mucus, responsible for its viscoelastic and gel-forming properties that enable mucociliary clearance of pathogens and particles. Aberrant mucin production is a clinically documented hallmark of asthma, COPD, and cystic fibrosis. Research on airway mucin regulation spans basic science to clinical measurement strategies.

• mugwortScientific

  Broncholytic and antispasmodic effects on airway smooth muscle have been pharmacologically demonstrated for A. vulgaris via dual muscarinic and calcium channel blockade. The dominant essential oil constituent 1,8-cineole provides additional mucolytic and anti-inflammatory respiratory actions. Traditional use as an expectorant for bronchitis and cough is documented across European and Asian systems.

• NAC (N-acetyl cysteine)Scientific

  N-Acetyl Cysteine (NAC) has well-established clinical evidence for supporting the respiratory system, primarily as a mucolytic and antioxidant agent. It is a proven adjunctive therapy for COPD, chronic bronchitis, bronchiectasis, and cystic fibrosis. High-dose NAC (1200 mg/day) has been shown in large RCTs to significantly reduce exacerbation rates in COPD. Evidence also supports benefit in ARDS and acute lung injury, while its role in asthma and idiopathic pulmonary fibrosis remains uncertain.

• nettleScientific

  A randomized double-blind placebo-controlled trial (n=74) evaluated nettle root extract for allergic rhinitis, showing significant symptom improvement, reduction in nasal eosinophil counts, and immune parameter changes versus placebo. Nettle extract inhibits H1 histamine receptors, mast cell degranulation, and prostaglandin synthesis in vitro—mechanisms central to allergic respiratory disease. Traditional use for asthma and coughs is additionally documented across multiple cultures.

• oleanolic acidScientific

  OA suppresses mast cell degranulation and Th2 cytokine production relevant to allergic respiratory conditions such as asthma and allergic rhinitis. Its anti-inflammatory mechanisms (NF-κB, COX-2 inhibition) are applicable to bronchial and upper airway mucosal inflammation.

• omega-3 fatty acidsScientific

  Multiple human and clinical studies demonstrate that omega-3 fatty acids (particularly EPA and DHA) are associated with attenuated lung function decline, reduced airway inflammation, and improved outcomes in conditions such as COPD, asthma, and acute lung injury/ARDS. The primary mechanism is anti-inflammatory: omega-3-derived mediators (resolvins, protectins) suppress pro-inflammatory cytokines and promote resolution of airway inflammation. Evidence is strongest for observational associations; large-scale RCT data remain limited and inconsistent, especially for asthma.

• onionScientific

  Onion is one of the most extensively studied plants for respiratory system effects. Its constituents produce tracheal smooth muscle relaxation, inhibit bronchoalveolar inflammatory infiltration, suppress respiratory inflammatory cytokines, and inhibit PAF-induced bronchial obstruction. A comprehensive 2021 PMC review documented its effects across the full spectrum of respiratory and allergic disorders.

• palmitateScientific

  Vitamin A palmitate maintains the integrity of respiratory tract epithelium and has been shown in RCTs to reduce bronchopulmonary dysplasia in premature infants. Retinyl palmitate is essential for normal lung development and epithelial repair after injury.

• panthenolScientific

  Dexpanthenol nasal and mucosal formulations are clinically used for the respiratory mucosa, with evidence from nasal surgery recovery, rhinitis sicca, and post-operative sore throat trials. A PubMed RCT confirmed dexpanthenol nasal spray improved mucociliary transit time after sinus surgery. A separate RCT confirmed 200 mg oral dexpanthenol prevents post-operative sore throat after intubation.

• peppermintScientific

  Peppermint's primary active compound, menthol, has been studied in multiple human trials for its effects on the respiratory system. Clinical evidence consistently shows that menthol produces a strong subjective sensation of improved nasal airflow and reduced dyspnea by activating TRPM8 cold-receptor channels, but objective measures of nasal resistance or airflow are not improved. There is also human-level evidence for antitussive (cough-suppressing) effects of menthol via TRP-channel modulation, and one small asthma trial showed reduced airway excitability with nebulized menthol. Overall, effects are primarily symptomatic and sensory rather than curative or structurally bronchodilatory.

• petasinesScientific

  Petasines — the sesquiterpene esters (petasin, isopetasin, neopetasin, S-petasin) derived from Petasites hybridus (butterbur) — have well-documented clinical and preclinical evidence for respiratory benefit, particularly in allergic rhinitis and asthma. Multiple randomized controlled trials have shown petasin-standardized extracts to be comparable to antihistamines in controlling hay fever symptoms, while animal models demonstrate suppression of airway hyperresponsiveness, eosinophil infiltration, and inflammatory cytokines. An open clinical trial also reported reductions in asthma attack frequency and improved lung function. The evidence is strongest for allergic rhinitis, with asthma data remaining largely preliminary.

• picrorhiza kurroaScientific

  P. kurroa has been used clinically and in preclinical studies for respiratory conditions including asthma and chronic bronchitis. Androsin mechanistically inhibits PAF-induced bronchial obstruction. Multiple Indian clinical trials (1975–1983) and a Cochrane-referenced review include P. kurroa for respiratory disease.

• pineScientific

  Pine bark has been used traditionally across cultures as an expectorant and antimicrobial for respiratory complaints (coughs, bronchitis, asthma). Scientifically, two asthma RCTs (N=86) included in the Cochrane review studied Pycnogenol at 100 mg/day. The 2024 review of 39 RDP trials confirmed respiratory health and allergies as a documented domain. Traditional use spans Native American, TCM, and European herbal practice.

• pine barkScientific

  Pycnogenol has been tested in RCTs for asthma and allergic rhinitis, with documented reductions in leukotriene levels, improved breathing, and reduced nasal/ocular allergy symptoms. The 2024 Frontiers review confirmed respiratory health and allergies as a validated RDP trial domain across three studies. Anti-inflammatory and antihistamine mechanisms are central.

• pineappleScientific

  Bromelain has clinical evidence for respiratory benefit in sinusitis (multiple trials), and mechanistic/animal evidence for asthma and allergic airways disease. It reduces mucosal swelling, mucus secretion, and inflammatory mediators throughout the respiratory tract.

• pistacia integerrima gallScientific

  The respiratory system is the primary traditional and scientific focus of P. integerrima galls. Extensive preclinical evidence supports bronchodilatory, mast-cell stabilizing, anti-inflammatory, expectorant, and antitussive activities. The 2026 Springer review and a 2014 PubMed mechanistic study provide the strongest scientific evidence, with limited clinical observations also supporting respiratory benefits.

• plantagoScientific

  Plantago lanceolata and P. major have comprehensive evidence for respiratory system support: Commission E and ESCOP monograph endorsement for airway catarrh, clinical RCT evidence in acute bronchitis, clinical improvements in asthmatic lung function (FEV1/FVC), and antiviral properties relevant to respiratory infections.

• plantainScientific

  Plantago has scientific evidence across multiple respiratory endpoints: an RCT in acute bronchitis, antitussive effects in guinea pig models, registered EU herbal medicine status for P. lanceolata for respiratory catarrh, Commission E recognition, and in vitro evidence in bronchial and tonsil epithelial cells. Mucilage, anti-inflammatory, and antimicrobial properties all act within the respiratory system.

• platycodonScientific

  Platycodon grandiflorum (Jiegeng/balloon flower root) has millennia of documented use in Traditional Chinese Medicine for cough, phlegm, and sore throat, and is listed in the Chinese Pharmacopoeia for these indications. Modern pharmacological studies confirm that its active saponins — principally platycodin D — and polysaccharides produce measurable antitussive and expectorant effects via stimulation of bronchial secretions and inhibition of airway inflammation. Preclinical in vivo studies demonstrate suppression of cough reflex, reduction of eosinophilic airway inflammation in asthma models, and attenuation of LPS-induced acute lung injury through the PI3K/Akt and NF-κB pathways. Human clinical evidence remains limited and mostly indirect; one small retrospective clinical study (n=22) found significant voice and vocal-fold improvement when Platycodon was used as part of TCM combination therapy.

• platycodon rootScientific

  Platycodon root (Platycodon grandiflorus, 'Jie Geng') has extensive documented use in TCM for respiratory ailments and is listed in multiple national pharmacopeias. Its primary bioactive triterpenoid saponins—especially platycodin D and platycodin D3—demonstrate expectorant, antitussive, and anti-inflammatory activity in preclinical models, with anti-inflammatory effects operating via suppression of NF-κB signaling and pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6. Modern clinical experience (particularly in East Asian medicine) supports its use in chronic pharyngitis, laryngitis, bronchitis, and related conditions, though large-scale randomized controlled trials in humans remain limited.

• poppyScientific

  Codeine and noscapine from P. somniferum are pharmaceutically validated antitussives that suppress cough via the respiratory system. P. rhoeas has traditional use as an expectorant and antitussive. Papaverine relaxes bronchial smooth muscle. The respiratory system is thus a key target of poppy alkaloids both scientifically and traditionally.

• purslaneScientific

  A clinical trial (n=13 asthmatic patients) found oral purslane extract produced pulmonary function improvements comparable to theophylline. In vitro and review data confirm smooth muscle-relaxant bronchodilatory properties. Traditional use for asthma, cough, excess mucus, and shortness of breath is documented globally across multiple ethnobotanical traditions.

• quercetinScientific

  Quercetin has documented human/clinical evidence supporting its role in respiratory health, primarily through antioxidant, anti-inflammatory, mast cell-stabilizing, and antiviral mechanisms. Clinical trials in COPD patients show reductions in inflammatory and oxidative stress markers with quercetin supplementation, and a meta-analysis of RCTs found benefits in COVID-19 respiratory outcomes. Evidence in upper respiratory tract infections is more mixed, with some trials showing benefit only in specific athletic or older-adult populations. Bioavailability remains a key limitation.

• reishi mushroomScientific

  TCM classified reishi as a primary lung tonic used for 'lung Qi deficiency,' chronic cough, and asthma-like presentations. Modern research shows ganoderic acid A alleviates OVA-induced asthma in mice and that reishi extracts modulate Th2 immune responses central to allergic airway disease. Life Extension cites clinical studies supporting a role for reishi in calming asthma and allergic responses.

• rose hipsScientific

  Rose hips support the respiratory system primarily through high vitamin C content that reduces duration and severity of upper respiratory infections (8–14% reduction by Cochrane-level meta-analysis). Quercetin's mast cell-stabilizing and antihistamine-like properties may reduce airway hypersensitivity. Traditional use for coughs, colds, and chest ailments is broadly documented across European and Asian herbal traditions.

• rosmarinic acidScientific

  Rosmarinic acid has demonstrated anti-inflammatory effects in the respiratory system in human clinical trials (seasonal allergic rhinoconjunctivitis) and preclinical asthma and lung injury models. It reduces airway eosinophilia, IgE, Th2 cytokines, and mucosal inflammatory cell infiltration. A gut-lung axis mechanism has been identified in preclinical asthma studies.

• serratiopeptidaseScientific

  Serratiopeptidase has the broadest and most consistent clinical evidence in the respiratory system, acting as both a mucolytic and anti-inflammatory agent. Multiple RCTs and prospective trials in chronic airway disease, sinusitis, bronchitis, and ENT disorders support its use for reducing sputum viscosity, neutrophil burden, and respiratory symptoms. It was historically approved in Japan as a mucolytic/anti-inflammatory agent.

• sphaeranthus indicusScientific

  S. indicus has experimentally confirmed bronchodilatory and mast cell stabilizing activities, both directly relevant to respiratory health. Traditional use in Ayurveda and Siddha covers cough, asthma-like symptoms, and nasal congestion.

• SPMs (specialized pro-resolving mediators)Scientific

  SPMs are produced endogenously in respiratory tissue and are critical regulators of airway and alveolar inflammation. Deficiencies in SPMs have been confirmed in human samples from asthma, COPD, and cystic fibrosis patients. SPM analogs have entered clinical trials for respiratory conditions.

• sulforaphaneScientific

  Sulforaphane induces Nrf2-driven phase II antioxidant enzymes in nasal and bronchial mucosa, attenuates nasal allergic responses to pollutants, and suppresses macrophage-driven inflammation in COPD cells. Multiple human clinical studies confirm airway-level bioactivity, though clinical symptom benefits in asthma/COPD are inconsistent.

• sweet flagScientific

  Bronchodilatory, expectorant, and antispasmodic actions of A. calamus on the respiratory system are pharmacologically documented, with a 2010 J. Ethnopharmacology study confirming multi-pathway bronchodilatory effects. Traditional classification as an expectorant and antispasmodic for respiratory diseases is extensive.

• thymeScientific

  Thyme (Thymus vulgaris) has well-documented use for respiratory conditions, particularly productive cough, acute bronchitis, and upper respiratory tract infections. Its key bioactive compound, thymol, exerts bronchospasmolytic, secretomotoric, and antimicrobial effects on airway tissue. Multiple placebo-controlled clinical trials support its efficacy in combination preparations, and it holds formal regulatory recognition from the EMA, ESCOP, WHO, and German Commission E for these indications. The EMA's HMPC classifies thyme-only preparations under 'traditional use' due to the lack of placebo-controlled monotherapy RCTs, while combination products (thyme/ivy, thyme/primrose) have demonstrated statistically significant superiority over placebo in RCTs.

• thymolScientific

  Thymol, the principal phenolic monoterpene in thyme (Thymus vulgaris) essential oil, has documented clinical use for acute bronchitis and upper respiratory tract infections, supported by randomized controlled trials and regulatory recognition by the EMA. Its key respiratory actions include secretolytic (mucus-thinning), antispasmodic, and antimicrobial effects. Clinical preparations containing thymol—typically in combination with other herbal extracts—have shown efficacy comparable to synthetic secretolytics such as ambroxol. The EMA's HMPC has assessed and referenced the clinical evidence base for thyme herba, of which thymol is a principal quality marker.

• thymusScientific

  Thymus vulgaris acts on the respiratory system through multiple complementary mechanisms: spasmolytic (bronchial smooth muscle relaxation), secretolytic (mucus fluidity enhancement), expectorant, antimicrobial, and anti-inflammatory. It is formally approved by the German Commission E, ESCOP, and EMA HMPC for respiratory indications. Multiple RCTs confirm clinical benefit for productive cough and acute bronchitis.

• turmericScientific

  Curcumin, the active polyphenol in turmeric, has been evaluated in human clinical trials for respiratory conditions including asthma and COPD. Mechanistically, it inhibits pro-inflammatory mediators such as TNF-α and interleukins in airway tissue. Clinical evidence is emerging but remains limited in scale; larger, well-powered trials are still needed to confirm efficacy.

• tylophoraScientific

  Tylophora indica (also known as Tylophora asthmatica) has been used in Ayurvedic medicine for centuries to treat bronchial asthma, bronchitis, and allergic rhinitis. Multiple human clinical trials — including crossover double-blind and placebo-controlled designs — conducted in the 1960s–1980s reported symptom relief in asthma patients, though later well-designed trials produced mixed results. Its primary bioactive alkaloid, tylophorine, demonstrates anti-inflammatory and mast-cell-inhibiting activity in laboratory studies. Overall, human evidence exists but remains inconsistent and methodologically dated, warranting cautious interpretation.

• tylophorineScientific

  Tylophorine is the principal alkaloid of Tylophora indica (syn. T. asthmatica), a plant with deep roots in Ayurvedic medicine for respiratory disorders including bronchial asthma and bronchitis. Multiple double-blind, controlled human clinical trials have demonstrated short-term improvements in asthma symptom severity, attack frequency, and lung function measurements with Tylophora preparations. Laboratory evidence shows tylophorine suppresses mast-cell activity and exerts anti-inflammatory and immunomodulatory effects, providing mechanistic support for these observations. A Cochrane systematic review confirmed short-term clinical benefit but noted positive effects were not maintained beyond 12 weeks, and significant gastrointestinal adverse effects limit chronic use.

• vasicineScientific

  Vasicine, the principal quinazoline alkaloid from Adhatoda vasica, has well-documented bronchodilatory, antitussive, and anti-inflammatory effects on the respiratory system supported by in vitro, in vivo, and clinical evidence. Its bronchodilating activity has been demonstrated both in vitro and in vivo, and it has proven antitussive activity comparable to codeine in animal models. Clinically, vasicine's synthetic derivative bromhexine—and its metabolite ambroxol—have been extensively tested in humans with respiratory diseases, validating the pharmacological basis of vasicine's respiratory actions. The compound has been used in traditional Ayurvedic and Unani medicine for over 2,000 years for cough, asthma, and bronchitis.

• vasicinoneScientific

  Vasicinone is a quinazoline alkaloid derived from Adhatoda vasica (vasaka) with well-documented bronchodilator and antiallergic activity studied in preclinical models. It has demonstrated bronchodilating activity in vitro and is also a principal metabolite of vasicine. Its structural derivative, bromhexine, has undergone clinical trials for respiratory conditions. Evidence is primarily preclinical (in vitro/in vivo animal models), with limited direct human clinical data on the isolated compound.

• vitamin AScientific

  Vitamin A is essential for the development, maintenance, and repair of the respiratory epithelium from the trachea to alveoli. Deficiency causes squamous metaplasia of respiratory mucosa, impairs mucociliary clearance, and is associated with increased respiratory morbidity and mortality. Clinical and Mendelian randomization evidence link vitamin A status to adult lung function.

• vitamin CScientific

  Vitamin C acts as a key antioxidant throughout the respiratory tract, protecting against oxidative damage from inhaled pollutants and inflammatory cells. Clinical evidence supports improved lung function in COPD with ≥400 mg/day supplementation, and signals of benefit exist in exercise-induced bronchoconstriction and respiratory infections.

• watercressScientific

  Human studies show PEITC derived from watercress inhibits lung carcinogen (NNK) activation in smokers, and cell line studies confirm anti-metastatic effects on lung cancer cells. Traditional use as a bronchitis and cough expectorant across multiple cultures is further supported by its well-documented isothiocyanate content. Germany recognizes watercress in phytotherapy for respiratory applications.

• xanthium (cockleburs)Scientific

  The respiratory system is the dominant organ system targeted by X. strumarium in both TCM clinical practice and modern preclinical research. Anti-allergic rhinitis activity is backed by multiple rodent studies and network pharmacology analysis. Anti-asthmatic and anti-bronchitis effects of xanthatin are demonstrated in animal models.

• yarrowScientific

  Animal studies document yarrow's bronchodilatory activity via calcium channel blockade in tracheal smooth muscle. Traditional use for respiratory conditions (fever, cold, phlegm, sinusitis) is Commission E-approved. Essential oil components including 1,8-cineole provide expectorant/mucolytic properties.

• agrimonyTraditional

  Agrimony has well-documented traditional use for respiratory conditions including bronchitis, cough, and pulmonary diseases across Central European and Asian folk medicine. Its expectorant, antimicrobial, and anti-inflammatory properties underpin this use. No clinical trial data in respiratory disease exist.

• alkanetTraditional

  Alkanet preparations are documented in European and Asian folk medicine for respiratory conditions including cough, bronchitis, bronchial catarrh, and throat inflammation. All plant parts are described as demulcent and expectorant. No pharmacological or clinical studies have evaluated these respiratory claims.

• allspiceTraditional

  Allspice is documented across Caribbean, Central American, and Ayurvedic traditions for respiratory conditions including chest infections, colds, flu, and congestion. Its volatile oil (including 1,8-cineole/eucalyptol) has expectorant properties, and eugenol exhibits antimicrobial activity against respiratory pathogens.

• alpinia galangalTraditional

  A. galanga rhizomes are widely used in Indian, Ayurvedic, and TCM traditions for respiratory conditions including asthma, bronchitis, bronchial catarrh, cough, and throat infections. ACA has demonstrated anti-asthmatic activity in mouse models. No standalone human respiratory clinical trials exist.

• apricotTraditional

  Apricot kernel (xing ren) is among the most commonly used TCM herbs for the respiratory system, appearing in classical formulas for cough, asthma, bronchitis, and wheezing. Its use is documented from ancient Chinese materia medica. It is classified as moistening the Lungs, descending Lung Qi, and expectorating phlegm. Several multi-herb TCM formulas containing apricot kernel have been clinically evaluated.

• ashwagandhaTraditional

  Ashwagandha has a documented traditional role in Ayurvedic medicine for respiratory conditions including asthma and bronchitis. Preclinical data suggests withaferin A reduces pulmonary eosinophilia and Type 2 cytokines in allergic airway models. No human clinical trials targeting the respiratory system specifically have been published.

• asparagusTraditional

  Multiple traditional medical systems document asparagus for respiratory conditions including asthma, bronchial asthma, and cough. A. cochinchinensis is listed in the Chinese Pharmacopoeia for asthma and cough. A. racemosus extracts show antitussive effects in preclinical studies. No human clinical trial evidence for respiratory outcomes exists.

• assam indigoTraditional

  The leaf (Da-Ching-Yeh) and root (Nan-Ban-Lan-Gen) of S. cusia are documented in multiple TCM sources for respiratory diseases including influenza, viral pneumonia, epidemic encephalitis B, mumps, and SARS-type coronavirus. Tryptanthrin shows in vitro activity against human coronavirus NL63.

• baicaleinTraditional

  Baicalein, a flavonoid from the root of Scutellaria baicalensis (Huang Qin), has well-documented traditional Chinese medicine use for respiratory conditions and a growing body of preclinical evidence supporting its anti-inflammatory, antioxidant, and antiviral activity in the respiratory system. In vitro and animal studies show efficacy against asthma, COPD, acute lung injury, and SARS-CoV-2, operating through NF-κB inhibition and cytokine suppression. However, as of early 2023, no completed human clinical trials specifically on baicalein for respiratory endpoints have been identified, meaning the link remains traditional/preclinical rather than clinically validated.

• bambooTraditional

  Bamboo is among the most extensively documented herbs for the respiratory system in TCM and Ayurveda. Multiple bamboo preparations (Succus Bambusae, zhuru, tianzhuhuang, vanshlochan) are used for cough, phlegm, bronchitis, pneumonia, asthma, and chest conditions. These uses are supported by over 2,500 years of documented practice across multiple Asian medical traditions.

• baobabTraditional

  Treatment of respiratory conditions including asthma, cough, and respiratory difficulty using baobab leaf preparations is documented in ethnobotanical literature from multiple sub-Saharan African countries. Leaf preparations are taken orally and the HerbalGram ethnopharmacological review specifically lists conditions including asthma and respiratory difficulty among those treated with baobab. The plant's anti-inflammatory properties are mechanistically relevant to airway inflammation.

• bayberryTraditional

  Bayberry has broad traditional use across the respiratory system for conditions including colds, flu, sore throat, bronchitis, laryngitis, sinusitis, asthma, and excess mucus. It was a principal ingredient in composition powder used for these conditions. TCM documents respiratory use for over 2,000 years.

• betelTraditional

  Betel leaf has deep traditional use as an expectorant and antitussive across Ayurvedic, Siddha, and Southeast Asian folk medicine for coughs, bronchitis, and asthma. Scientific evidence is limited to preclinical anti-inflammatory and antioxidant data; no human clinical trials support respiratory use.

• black pepperTraditional

  Black pepper is used in Ayurveda and traditional Chinese medicine as a respiratory herb for congestion, excess mucus, and respiratory infections. The Trikatu formula specifically addresses lung problems with sticky mucus. Piperine's TRPV1 activation and anti-inflammatory properties provide mechanistic plausibility.

• black spruceTraditional

  The respiratory system is black spruce's primary traditional therapeutic domain. British Herbal Pharmacopoeia, Indigenous traditions, and aromatherapy all document its use for coughs, colds, bronchitis, congestion, and catarrh. Its expectorant, mucolytic, and antimicrobial essential oil constituents are mechanistically appropriate.

• bonesetTraditional

  Boneset is a primary traditional herb for acute respiratory infections, classified in historical and contemporary herbalism as a diaphoretic, expectorant, and anti-inflammatory remedy for the respiratory mucosa. It is used across multiple respiratory conditions including colds, influenza, bronchitis, and nasopharyngeal catarrh. Its classification as an expectorant dates to Lockwood (1847) and continues in modern monographs. No clinical trials on respiratory outcomes exist.

• caesalpinia cristaTraditional

  C. crista is traditionally used for respiratory disorders including asthma in Ayurvedic, Unani, and Southeast Asian ethnomedicine. Traditional documentation across multiple independent systems is consistent and extensive, though no controlled preclinical respiratory studies are published.

• calendulaTraditional

  Calendula preparations are used traditionally for respiratory mucosal inflammation, including sore throat, tonsilitis, and cough. The EMA recognises oral mucosal use, which extends to pharyngeal application. Its antimicrobial, antiviral, and mucosal-healing properties support respiratory indications. No respiratory RCTs exist.

• carawayTraditional

  Caraway has traditional use as an expectorant and cough remedy in European, Moroccan, and Ayurvedic medicine for respiratory conditions. Its volatile oils are attributed with expectorant and antimicrobial activity in the respiratory tract. A peer-reviewed source confirms historical use in bronchopulmonary disorders.

• cardamomTraditional

  Cardamom is one of the primary respiratory herbs in Ayurvedic and South Asian medicine, used for cough, congestion, asthma, bronchitis, and mucus clearance. Its dominant compound 1,8-cineole has independently documented bronchodilatory and mucolytic properties. Clinical RCT evidence specific to cardamom for respiratory conditions is lacking; support is traditional with pharmacological plausibility.

• cassia barkTraditional

  Cassia bark is documented across TCM and Ayurvedic medicine as an expectorant, antitussive, and warming respiratory remedy used for coughs, bronchitis, and cold-type respiratory conditions. In vitro antiviral activity against influenza virus has been demonstrated. No respiratory-focused clinical trials with C. cassia bark as a primary intervention were identified.

• cat's clawTraditional

  Cat's claw is documented as an antiasthmatic and anti-allergic agent in Peruvian and Brazilian traditional medicine. The 2024 Frontiers systematic review confirms traditional use as an 'antiasthmatic agent' and animal models included asthma. Indigenous Ashaninka use for asthma is well-recorded. No human RCTs for respiratory endpoints exist.

• chamomileTraditional

  Chamomile inhalation is a traditional and Commission E-endorsed treatment for respiratory infections, bronchitis, hay fever, and mucous congestion. Its anti-inflammatory, antimicrobial, and mucolytic properties provide mechanistic plausibility. The American Botanical Council records use for acute respiratory infections and asthma. Dedicated human clinical trials for respiratory outcomes are absent.

• chen piTraditional

  Chen Pi enters the Lung meridian in TCM and is one of the most widely used herbs for respiratory phlegm conditions. It is a key ingredient in classical phlegm-transforming formulas and has preclinical anti-inflammatory and anti-asthmatic activity relevant to respiratory disease.

• chickweedTraditional

  Chickweed has consistent traditional use across multiple herbal systems for respiratory tract conditions, acting as an expectorant and demulcent for coughs, bronchitis, asthma, and sore throats. Saponins and mucilage are the proposed active constituents. No clinical evidence is available.

• chrysanthemumTraditional

  Chrysanthemum is connected to the Lung meridian in TCM and is traditionally used for respiratory complaints including cough, congestion, and respiratory infections. Antimicrobial and anti-inflammatory properties provide mechanistic support. No human clinical trials for respiratory system outcomes specifically have been conducted.

• cleaversTraditional

  Cleavers has traditional use for upper respiratory tract congestion, attributed to its anti-inflammatory and lymphatic effects reducing mucosal swelling. Documented in Western herbal traditions for colds, mucous congestion, and respiratory sequelae of febrile illness.

• clerodendrum indicumTraditional

  Clerodendrum indicum's most prominent and consistent traditional application across Ayurveda, Unani, and Southeast Asian folk medicine is respiratory. The root is used as an expectorant, antitussive, bronchodilator, and anti-asthmatic preparation across India, Laos, Myanmar, Indonesia, Nepal, and beyond. A bronchodilatory compound has been isolated in laboratory settings.

• cloveTraditional

  Clove and eugenol have longstanding traditional use across the respiratory system including expectorant, antispasmodic, anti-inflammatory, and decongestant properties. PMC reviews confirm eugenol's inclusion in medications for upper respiratory mucosa inflammation.

• coltsfootTraditional

  The respiratory system is the primary traditional domain of coltsfoot, used across Europe, Asia, and North America for coughs, asthma, bronchitis, emphysema, and airway irritation. Its Latin name Tussilago means 'cough dispeller.' Its demulcent, expectorant, and antispasmodic properties are documented across centuries.

• comfreyTraditional

  Comfrey has well-documented traditional use for respiratory conditions including bronchitis, pleurisy, persistent cough, and sore throat, historically administered as a leaf decoction or root tea. The mucilaginous content was believed to soothe and protect respiratory mucosa. No clinical trial evidence supports respiratory use, and oral comfrey is contraindicated.

• commiphoraTraditional

  Commiphora myrrh is recognized by ESCOP as supportive for pharyngitis and tonsillitis, and has traditional documented use for bronchitis, sinusitis, coughs, and catarrh across TCM, Ayurveda, and European herbalism. Clinical RCTs for respiratory indications are lacking.

• damianaTraditional

  Damiana is documented in traditional medicine as an expectorant, cough suppressant, and remedy for bronchitis and asthma-related conditions. Maya Indians named it 'broom for asthma.' It is listed for lung diseases related to tobacco in Mexican traditional medicine. No clinical respiratory studies exist.

• dog roseTraditional

  Dog Rose has documented traditional use for respiratory conditions including colds, bronchitis, coughs, and chest ailments across European and folk herbal medicine. The high vitamin C content and anti-inflammatory polyphenols provide mechanistic support. No human clinical trials for respiratory outcomes specifically have been conducted.

• elecampaneTraditional

  Elecampane (Inula helenium) has a well-documented tradition of use across European, Ayurvedic, and Traditional Chinese Medicine for respiratory conditions including bronchitis, asthma, whooping cough, and productive coughs with excess mucus. Its root contains sesquiterpene lactones (alantolactone, isoalantolactone) that demonstrate expectorant, bronchospasmolytic, anti-inflammatory, and antimicrobial activity in preclinical (in vitro and animal) models. The only human study involving elecampane in a respiratory context used a multi-herb combination syrup, making it impossible to attribute efficacy to elecampane alone. No human clinical trials isolating elecampane as a single agent for respiratory conditions have been conducted.

• fennelTraditional

  Fennel is documented in traditional Iranian medicine, Ayurveda, and European monographs (EMA, Commission E) as a respiratory herb with bronchodilatory, expectorant, and antispasmodic properties. Preclinical data support smooth muscle relaxation; human respiratory trials are absent.

• ferula assafoetidaTraditional

  Asafoetida is one of the primary traditional respiratory herbs documented in Ayurveda, Unani, European, and Middle Eastern systems, used for asthma, bronchitis, whooping cough, and mucus accumulation. The volatile oil is eliminated through the lungs, providing direct expectorant and bronchospasmodic effects.

• feverfewTraditional

  Feverfew has been used traditionally for respiratory complaints including asthma, wheezing, coughs, and colds. The NCCIH, PMC systematic review, and historical accounts by Dioscorides document these uses. Leukotriene inhibition provides mechanistic support, but no clinical trials exist.

• flowering quinceTraditional

  C. speciosa is documented in TCM for asthma, colds, sore throats, and influenza, with traditional use spanning thousands of years. Anti-influenza neuraminidase inhibition has been confirmed in vitro. No dedicated respiratory system clinical trials exist.

• ganodermaTraditional

  Ganoderma lucidum has extensive documented traditional use for respiratory conditions including asthma, bronchitis, and cough. Preclinical pharmacological studies confirm antitussive, bronchodilatory, and Th2-modulating effects. Modern reviews affirm clinical application potential for pulmonary diseases.

• glehnia rootTraditional

  The respiratory system is the primary body system targeted by glehnia root in East Asian traditional medicine, with documented uses including cough, phlegm, lung heat, bronchitis, asthma, rhinitis, and dry throat across TCM, Japanese, Korean, and Mongolian traditions.

• goldenrodTraditional

  Goldenrod is recognized in European and North American herbal medicine as a primary herb for the respiratory system, with documented traditional use for sinusitis, nasal catarrh, bronchitis, sore throat, and seasonal respiratory conditions. It is classified as anticatarrhal, diaphoretic, and anti-inflammatory in professional herbal materia medica. No specific respiratory RCTs have been conducted.

• goldensealTraditional

  Goldenseal is one of the most widely used traditional herbs for respiratory tract conditions, specifically for its effects on mucous membranes of the upper and lower respiratory tract. Its use for upper respiratory infections, bronchitis, mucus congestion, and related conditions is extensively documented.

• gooseberryTraditional

  Traditional Ayurvedic and Unani medicine have documented amla for respiratory conditions including asthma, bronchitis, and respiratory infections for millennia. A clinical pilot study evaluated amla for cardio-respiratory improvement in smokers. Anti-inflammatory mechanisms support this.

• greek mountain teaTraditional

  GMT holds formal EU traditional herbal medicine status (EMA/HMPC) specifically for relief of cough associated with cold. Traditional use across the entire respiratory system is one of the most consistently documented applications of GMT throughout its history. Anti-inflammatory and antimicrobial properties provide biological plausibility for respiratory support.

• guggulTraditional

  Guggul is used in Ayurveda as an expectorant and anti-Kapha agent for respiratory conditions including bronchitis, cough, nasal catarrh, and laryngitis. Inhalation of guggul resin fumes is a traditional application. No clinical trials have examined guggul for respiratory conditions.

• ho woodTraditional

  Ho wood essential oil has a well-established traditional use in French aromatherapy for respiratory conditions including colds, flu, bronchitis, and respiratory infections, attributed to its linalool-driven antibacterial and anti-infectious properties. Aroma-Zone notes it was 'historically widely used for clearing and purifying the respiratory tract.' Traditional aromatic medicine also recommends it for respiratory problems in infants and young children. Scientific support derives from linalool's antimicrobial activity but no respiratory-specific clinical trials exist for ho wood.

• holarrhena antidysentericaTraditional

  H. antidysenterica bark and leaves are used in Ayurvedic practice, British Materia Medica, and multiple Asian traditional systems for chronic bronchitis, asthma, chest infections, and bronchopneumonia. Anti-inflammatory alkaloids provide pharmacological plausibility. No modern clinical respiratory trials exist.

• hollyTraditional

  I. aquifolium leaves are documented in traditional European herbalism as expectorant, diaphoretic, and treatment for catarrh, chest congestion, pleurisy, and general respiratory illness. Trace methylxanthines in the leaves may provide mild bronchodilatory activity.

• horehoundTraditional

  Horehound (Marrubium vulgare) has an extensively documented traditional role as an expectorant and cough remedy, recognized formally by the EMA's HMPC, ESCOP, German Commission E, and the British Herbal Pharmacopoeia. Its primary active constituent, marrubiin (a labdane diterpene), is proposed to stimulate bronchial mucous membranes and relax bronchial smooth muscle, promoting mucus clearance. Preclinical (animal and in vitro) data support expectorant and anti-inflammatory activity, but robust human clinical trials are absent, keeping the evidence base firmly in the traditional-use category.

• immortelleTraditional

  H. italicum has well-documented traditional use for respiratory conditions including bronchitis, cough, asthma, colds, and as an expectorant throughout Mediterranean Europe. In vitro antibacterial activity against key respiratory pathogens has been demonstrated, but no human clinical trials exist.

• indian gum arabic treeTraditional

  Vachellia nilotica has been used for thousands of years for respiratory ailments including asthma, bronchitis, coughs, and chest pain. Anti-inflammatory and antispasmodic properties provide mechanistic rationale. Respiratory ailments are listed among the plant's primary traditional indications.

• indian sarsparillaTraditional

  Indian sarsaparilla has extensive traditional documentation for respiratory conditions including asthma, bronchitis, cough, and dyspnea across Ayurveda, Siddha, Unani, and folk medicine. Anti-asthmatic and demulcent properties are noted in preclinical pharmacological listings. The root's membrane-soothing properties are particularly relevant.

• indigo leavesTraditional

  Indigo leaves are documented in Ayurvedic, Siddha, and TCM traditions for respiratory conditions including bronchitis, asthma, and cough. The plant and its extracts are listed as expectorant and anti-inflammatory in traditional pharmacopoeias, with leaves specifically used for these conditions.

• jujubeTraditional

  Jujube is traditionally used across Asian and Middle Eastern medicine for respiratory conditions including cough, asthma, bronchitis, and throat irritation. Preclinical anti-allergic and antihistaminic effects are documented. Jujube syrup/decoction for cough and sore throat is a standard traditional preparation. No human respiratory RCTs are available.

• knotweedTraditional

  In TCM, Hu Zhang (P. cuspidatum) enters the lung meridian and is used to resolve phlegm, ease cough, and treat bronchitis. WebMD notes documented traditional use for bronchitis and cough. In vitro studies show PC constituents inhibit airway smooth muscle proliferation and mucin expression. No human RCTs confirm respiratory clinical efficacy.

• lavenderTraditional

  Lavender has traditional use in European herbal medicine for respiratory conditions including cough, bronchitis, and upper respiratory tract infections, primarily administered by inhalation. Modern scientific evidence confirms lavender oil has antimicrobial properties relevant to respiratory pathogens, and inhalation delivery itself engages respiratory physiology. Dedicated RCTs for lavender in respiratory diseases are lacking.

• lemongrassTraditional

  Lemongrass is documented in traditional medicine for respiratory complaints including cough, sore throat, cold, and flu symptoms. Its antitussive classification in pharmacological reviews and use in aromatic inhalations are well-documented. Antimicrobial and anti-inflammatory properties are mechanistically relevant but no human respiratory RCTs exist.

• lilacTraditional

  European and Asian ethnopharmacological traditions document extensive use of S. vulgaris and related Syringa species for respiratory conditions including cough, bronchitis, and bronchial disease. The antimicrobial, antiviral, and anti-inflammatory activities confirmed preclinically provide biological support.

• lilyTraditional

  Lily bulb's primary TCM indication is the Lung meridian—moistening the lungs, relieving cough, and clearing heat. It is listed in the Chinese Pharmacopoeia for cough and hemoptysis. Across Asian medical systems, it is used for respiratory diseases, cough, and bronchitis. Anti-inflammatory activity in airway models and saponin-mediated expectorant properties provide pharmacological support.

• lobeliaTraditional

  Lobelia (Lobelia inflata) has a well-documented traditional use for respiratory conditions including asthma, bronchitis, whooping cough, and coughs, primarily attributed to its major alkaloid α-lobeline. Pharmacologically, α-lobeline acts as a respiratory stimulant by activating carotid and aortic body chemoreceptors, relaxing lung tissue, and promoting expectoration. However, controlled human clinical trials specifically evaluating lobelia for respiratory indications are lacking, and current evidence does not support its clinical recommendation for any respiratory condition. The FDA prohibited OTC lobeline products for smoking cessation in 1993, reflecting the absence of proven efficacy.

• magnoliaTraditional

  Magnolia bark has longstanding traditional use in TCM and Kampo for respiratory conditions including asthma, cough, and congestion. It is an ingredient in the Kampo formula Saiboku-to used for asthma. One clinical trial (148 asthma patients) supports bronchial benefit as add-on therapy. Honokiol and magnolol relax airway smooth muscle in preclinical models.

• mangoTraditional

  Mango leaves and bark are traditionally used across Ayurvedic and folk medicine systems for respiratory conditions including asthma, bronchitis, and cough. Mango leaf tea is used to soothe irritated respiratory passages. The anti-inflammatory properties of mangiferin may provide pharmacological plausibility for airway benefits.

• marjoramTraditional

  Marjoram is documented in multiple traditional medicine traditions as an expectorant and respiratory remedy for coughs, colds, bronchitis, and congestion. Modern herbal medicine and pharmacological research support antimicrobial and anti-inflammatory mechanisms relevant to respiratory health.

• melaleuca alternifoliaTraditional

  First Nations Australians, particularly the Bundjalung people, have a well-documented tradition of inhaling crushed M. alternifolia leaves and steam preparations to treat coughs, colds, and upper respiratory infections. No controlled human clinical trials have been published for respiratory conditions.

• milkweedTraditional

  The respiratory system is the primary traditional medicinal focus of milkweed, especially A. tuberosa (pleurisy root), which was listed in the US Pharmacopeia for over 80 years. Its expectorant, antispasmodic, and diaphoretic properties were applied to pleurisy, pneumonia, bronchitis, asthma, and influenza. No clinical evidence of efficacy exists.

• morusTraditional

  Morus alba leaves and root bark are classical TCM herbs for the respiratory system. Sang Ye is used for Wind-Heat cough and lung heat, while Sang Bai Pi (root bark) is used for wheezing and phlegm congestion. Both are listed in the Chinese Pharmacopoeia for respiratory indications.

• mulberryTraditional

  Multiple parts of the mulberry plant are documented in the Chinese Pharmacopoeia for respiratory conditions. Mulberry leaf treats dry cough and Wind-Heat respiratory infections; root bark treats deeper bronchial conditions with wheezing and phlegm. Expectorant and antibacterial properties are reported.

• mulleinTraditional

  Mullein (Verbascum thapsus) has extensive, cross-cultural traditional use for respiratory conditions including coughs, bronchitis, and asthma, documented across European, Irish, Turkish, and Native American folk medicine. Its leaves and flowers contain mucilage, saponins, and flavonoids that provide plausible mechanistic explanations — demulcent coating of airways, expectorant loosening of mucus, and anti-inflammatory activity. Preclinical evidence (in vitro and animal studies) supports these mechanisms, but large, controlled human clinical trials are absent, keeping the evidence firmly in the traditional category.

• mustardTraditional

  Mustard's impact on the respiratory system spans decongestant, mucolytic, and antimicrobial actions—all well documented in folk medicine and mechanistically supported by AITC pharmacology. The long history of mustard plaster use for bronchitis, pneumonia, and congestion reflects consistent cross-cultural recognition of respiratory benefit.

• myrobalanTraditional

  TC is traditionally used across Ayurveda, Tibetan, and South Asian folk medicine for asthma, chronic cough, dyspnea, and sore throat. It is described as supporting normal secretions of respiratory mucosal membranes. Preclinical evidence includes potential IgE-dependent bronchial asthma activity.

• myrrhTraditional

  Myrrh is classified as an expectorant and anti-inflammatory agent for the respiratory system across multiple traditional systems. It is used for bronchitis, coughs, nasal congestion, chest infection, and asthma. The PMC pharmacological review and multiple herbal monographs document this interaction.

• neem treeTraditional

  Neem is used in traditional Ayurvedic medicine for respiratory disorders including asthma, bronchitis, and cough, documented in ScienceDirect and caring sunshine traditional use sources. Anti-inflammatory and antimicrobial properties provide mechanistic plausibility. Human clinical trials for respiratory conditions with neem are absent.

• nut grassTraditional

  C. rotundus is used in Ayurveda and Unani for bronchitis, cough, and respiratory conditions. The antispasmodic, anti-inflammatory, and antitussive properties provide mechanistic support. Traditional classification includes antitussive and expectorant uses.

• ophiopogonTraditional

  Ophiopogon japonicus has a primary TCM indication for the respiratory system, specifically for lung yin deficiency manifesting as dry cough, sore throat, and difficult expectoration. It is documented across Chinese, Japanese, and Southeast Asian traditional medicine for respiratory conditions.

• ophiopogon rootTraditional

  The lung meridian is one of three primary targets of ophiopogon root in TCM and the Chinese Pharmacopoeia. The herb is prescribed for lung yin deficiency, dry cough, hemoptysis, and respiratory dryness across multiple classical and pharmacopoeial sources. Preclinical antitussive and anti-inflammatory activities provide mechanistic support.

• orangeTraditional

  Orange has extensive traditional use across Chinese, Ayurvedic, and European medicine for respiratory health including cough, bronchitis, asthma, and mucus clearance. Vitamin C from orange provides some scientifically supported respiratory immune protection. d-Limonene in orange peel has pharmacologically plausible expectorant and mucolytic actions.

• oreganoTraditional

  Oregano has one of the longest continuous traditional use records for respiratory conditions of any herb — documented from Hippocrates through medieval Europe, Turkish, Chinese, and Iranian traditional medicine. Uses include cough, bronchitis, asthma, upper respiratory infection, and phlegm. Antimicrobial and anti-inflammatory mechanisms provide biological plausibility. Human clinical evidence specific to respiratory endpoints is limited.

• oriental arborvitaeTraditional

  The respiratory system is the primary traditional target for P. orientalis leaves, which are listed in the Chinese Pharmacopoeia for chronic bronchitis, bronchiectasis, asthma, excessive mucus, and cough. Classical TCM texts from 934 AD document this use. Anti-inflammatory activity on airway tissue provides mechanistic support.

• paederia foetidaTraditional

  P. foetida is used in northeastern India and Chinese traditional medicine for respiratory disorders including asthma, bronchitis, and cough. Antitussive activity has preclinical support from a study in cats. The plant has expectorant properties and is administered via steam inhalation in folk practice.

• parsleyTraditional

  Parsley is listed in traditional and folk medicine for respiratory conditions including coughs and upper respiratory catarrh (sniffle, otitis), consistent with its antimicrobial and anti-inflammatory volatile oil content. These uses are documented in ethnopharmacological reviews but lack clinical trial support.

• partheniumTraditional

  Respiratory disorders including asthma, bronchitis, and coughs are documented traditional uses of feverfew listed by NCCIH and the PMC systematic review. A 2025 systematic review (Taylor & Francis) specifically addressed parthenolide and derivatives in respiratory tract diseases. Mechanistic evidence exists but human clinical trials are absent.

• peachTraditional

  Multiple parts of the peach plant—leaves (expectorant), kernels (antitussive, antiasthmatic), and flowers—are documented for respiratory conditions including bronchitis, whooping cough, asthma, and chest congestion across traditional systems. The kernel enters the Lung channel in TCM.

• pearTraditional

  In TCM, pear is the quintessential respiratory system food, used to moisten the lungs, clear heat, reduce phlegm, and soothe the throat and bronchi. This use is documented in classical texts and contemporary TCM practice across China, Korea, and Japan. Modern evidence for polyphenol lung-protective activity exists but clinical trial data for respiratory endpoints are not confirmatory.

• pennycressTraditional

  Pennycress is classified as an expectorant in multiple traditional medical systems and was used for respiratory conditions including bronchial irritation, lung congestion, and conditions involving pus in the lungs. The seeds were particularly valued in Tibetan medicine for pulmonary complaints.

• perillaTraditional

  Perilla is a foundational TCM herb for respiratory conditions, with documented uses spanning over 2,000 years for cough, asthma, bronchitis, and excess phlegm. Multiple classical TCM formulas use perilla specifically for respiratory indications. Modern cell and animal studies confirm anti-inflammatory effects on respiratory epithelium.

• polygalaTraditional

  P. tenuifolia is classified in the Chinese Pharmacopoeia with Lung meridian affinity, and has over 1,000 years of use as an expectorant, antitussive, and phlegm-dissipating herb in TCM. Preclinical studies confirm antitussive, expectorant, and anti-inflammatory activities in bronchitis and COPD animal models.

• polygala rootTraditional

  The respiratory system is a formally documented secondary target of Polygala root in the Chinese Pharmacopoeia, which lists Lung meridian entry and phlegm-dissipating/expectorant/anti-asthmatic properties. Multiple preclinical studies validate antitussive, expectorant, and anti-inflammatory effects in respiratory models.

• prunusTraditional

  Prunus africana bark preparations are documented in traditional African medicine for respiratory conditions including chest pain and chest infections, particularly in South Africa, Cameroon, and East Africa. The 2024 comprehensive review documents this use across multiple African communities. Pharmacological mechanistic evidence for anti-inflammatory effects in respiratory tissue exists but clinical respiratory trials are absent.

• pterocarpus marsupiumTraditional

  Traditional Ayurvedic use of P. marsupium for asthma, bronchitis, and cough is documented in multiple peer-reviewed ethnobotanical reviews. No preclinical respiratory-specific studies have been identified.

• punarnavaTraditional

  Punarnava is listed in Ayurvedic texts for cough, asthma, breathing disorders, and chest conditions, with documented expectorant and anti-histaminic properties. An ethanolic root extract showed protection against histamine-induced dyspnea in animals. Traditional use for respiratory complaints spans Ayurveda, Siddha, and tribal medicine across Asia and Africa.

• queen of the meadowTraditional

  The EMA HMPC monograph recognizes queen of the meadow as a traditional herbal product for symptoms of the common cold, placing it within the respiratory system domain. Its diaphoretic action reduces fever in respiratory infections, and antitussive properties are documented in the German pharmacopoeia empirical medicine tradition.

• quillajaTraditional

  Quillaja saponaria has an extensive traditional record of use for respiratory system ailments, particularly as an expectorant for cough, bronchitis, and chest complaints among Andean peoples. The saponins stimulate more fluid airway mucus to aid clearance. Evidence is traditional with no controlled clinical respiratory trials.

• radishTraditional

  Radish is documented across TCM, Ayurveda, and European folk medicine as an expectorant and mucolytic agent for respiratory conditions including bronchitis, cough, and phlegm congestion. RxList lists respiratory tract mucus and bronchitis as traditional indications. No clinical respiratory trials have been conducted.

• red cloverTraditional

  Red clover flowers have an extensively documented traditional use across the respiratory system, including for asthma, bronchitis, whooping cough, and as an expectorant to clear mucus. This use is documented by drugs.com, MSKCC, ScienceDirect, EBSCO Research, and multiple herbal monographs from European, Chinese, and North American traditions. No clinical trial evidence exists.

• red rootTraditional

  Ceanothus americanus has a broad and consistently documented traditional relationship with the respiratory system, spanning use for asthma, chronic bronchitis, whooping cough, coughs, and mucus conditions. The Eclectic tradition and Native American medicine both documented this, and the plant's expectorant, antispasmodic, and mucolytic properties provide a mechanistic basis.

• rosa californicaTraditional

  Infusions of Rosa californica petals and hips were used by California indigenous peoples and early settlers to treat respiratory illness including coughs, sore throat, and cold-like symptoms. This use parallels that of related Rosa species in European and other traditional herbal systems.

• sageTraditional

  Sage is documented in traditional European medicine for bronchitis, cough, sore throat, laryngitis, sinusitis, and tonsillitis, attributed to its antimicrobial, expectorant, and astringent volatile oil components. Commission E and ESCOP recognize sage for throat and mucosal inflammations. No RCTs specifically targeting respiratory outcomes could be identified.

• schisandrinsTraditional

  Classical TCM pharmacopeias document Wu Wei Zi as a primary herb for chronic cough and wheezing due to lung qi deficiency, with actions including 'containing leakage of lung qi and stopping cough.' MSKCC confirms this traditional use. Clinical trials specifically testing schisandrins for respiratory outcomes have not been conducted.

• schizonepetaTraditional

  Schizonepeta is a cornerstone TCM herb for respiratory conditions, used for over 2,000 years for colds, cough, nasal congestion, and sore throat. Preclinical anti-inflammatory and antiviral properties support its respiratory relevance. Formula-based clinical use is documented but no isolated human respiratory trials exist.

• scrophularia rootTraditional

  Scrophularia root has traditional use for respiratory conditions including pharyngitis, laryngitis, and throat infections. S. buergeriana is specifically used in TCM for pharyngitis and related respiratory tract conditions. The root appears in TCM respiratory formulas. Anti-inflammatory properties are mechanistically relevant. A substantial clinical evidence base specific to respiratory disease is absent.

• sheep's sorrelTraditional

  Traditional medicine has included sheep's sorrel for respiratory conditions including inflammation and excessive mucus. The plant's diaphoretic action was used for respiratory infections with fever. No clinical evidence exists for respiratory use.

• siler rootTraditional

  The dried root of SD is explicitly listed in the PMC comprehensive review as used for respiratory diseases in Chinese herbal medicine. Its TCM applications—releasing exterior wind-cold, suppressing cough, and clearing early respiratory pathogens—have over 2,000 years of documentation. Preclinical antiallergic and anti-inflammatory findings are supportive but limited.

• skullcapTraditional

  S. baicalensis has a 2,000-year TCM history for respiratory infections including pneumonia and bronchitis. It is documented in Ben Cao Gang Mu for 'upper respiratory tract infections' and used in clinical Chinese medicine for 'acute pulmonary infection.' Baicalin has documented anti-inflammatory effects in cigarette smoke-induced pulmonary models.

• slippery elmTraditional

  Slippery elm (Ulmus rubra) has a well-documented traditional role in supporting the respiratory system, primarily via its mucilage content, which coats and soothes irritated mucous membranes of the throat and upper airways. It has historically been used for sore throat, cough, bronchitis, and related upper respiratory complaints. However, dedicated human clinical trials are absent, and authoritative sources consistently characterize the evidence as traditional rather than scientifically validated.

• slippery elm barkTraditional

  Slippery elm bark (Ulmus rubra) has a well-documented history of traditional use for respiratory complaints—particularly sore throats, coughs, and bronchitis irritation—among Native American peoples and later European settlers. Its proposed mechanism centers on a high-polysaccharide mucilage that forms a gel-like coating over irritated mucous membranes of the upper respiratory tract. No robust clinical trials specifically examining slippery elm for respiratory conditions have been published; institutional sources (NCBI LiverTox, Memorial Sloan Kettering) confirm that human data for coughs and bronchitis are lacking. Its use in this context remains traditionally justified rather than scientifically validated.

• smartweedTraditional

  Respiratory support is a documented traditional use of smartweed in North and South American folk medicine, as well as in traditional Chinese medicine. The plant's pungent volatile oils and antimicrobial properties underpin traditional respiratory applications.

• solomon's sealTraditional

  Solomon's seal is a classic TCM lung herb, listed in the Chinese Pharmacopoeia for dry cough and lung dryness. It is used as a demulcent, expectorant, and lung moistener across TCM, Ayurvedic, and Western herbal traditions. A PMC animal study (2023) investigated P. odoratum polysaccharide in lung injury.

• soursopTraditional

  Soursop is traditionally used for respiratory conditions including coughs and asthma across tropical Africa, Asia, and the Caribbean, and is listed among its documented traditional uses in multiple pharmacological reviews. No clinical trials on respiratory endpoints have been published.

• spearmint leafTraditional

  Spearmint has been traditionally used across multiple cultures for respiratory complaints including cough, congestion, bronchitis, and asthma. Its antispasmodic and anti-inflammatory properties may relax bronchial smooth muscle and reduce mucous membrane inflammation. No dedicated human clinical trials exist for spearmint in respiratory disease.

• spruceTraditional

  Spruce is one of the most comprehensively documented traditional remedies for respiratory health across multiple species and cultures. Shoots, needles, bark, and resin are all used for coughs, colds, bronchitis, lung congestion, and sinus complaints. The mucolytic, expectorant, and antiseptic terpene chemistry supports these applications.

• stillingiaTraditional

  Stillingia was used in traditional medicine to support the entire respiratory system, including the throat, larynx, bronchi, and lungs, through its expectorant and mucosal-stimulating properties. This use is documented in Eclectic medicine and Native American herbal practice. No clinical evidence exists.

• sunflowerTraditional

  Sunflower seeds and leaves have an extensive traditional use in respiratory medicine across multiple cultures, used for bronchial, laryngeal, and pulmonary affections, coughs, colds, bronchitis, and as an expectorant to clear mucus. These uses are documented in historical monographs and ethnomedicine records.

• swertiaTraditional

  Swertia chirayita is documented for use in respiratory conditions including bronchial asthma, cough, and related ailments across South Asian and Tibetan traditional medicine. Airways modulatory effects are noted in pharmacological reviews. No human clinical data for respiratory endpoints are available.

• tartarian asterTraditional

  Aster tataricus root is the principal TCM herb for the respiratory system, documented for over 2,000 years. It is listed in the Chinese Pharmacopoeia as an expectorant, antitussive, and antiasthmatic, and is included in compound preparations in Japanese Kampo medicine for respiratory disease. Preclinical pharmacology confirms expectorant, bronchodilatory, anti-inflammatory, and antiviral mechanisms.

• terminaliaTraditional

  T. chebula has extensive traditional use across Ayurvedic, Unani, and folk medicine for respiratory conditions including asthma, chronic cough, sore throat, and bronchitis. The Ayurvedic Pharmacopoeia lists it for cough and asthma. Its anti-inflammatory and antimicrobial properties provide mechanistic support. No clinical RCTs for respiratory endpoints were identified.

• tinospora cordifoliaTraditional

  T. cordifolia is used in traditional Indian medicine for asthma, bronchitis, and respiratory infections, and is an ingredient in the commercial polyherbal formulation Septilin for bronchitis. Anti-allergic and anti-inflammatory mechanisms support its respiratory relevance.

• trichosanthesTraditional

  Trichosanthes is attributed primarily to the lung meridian in TCM and is classified as an expectorant and phlegm-transforming herb with documented use for coughs, asthma, bronchitis, and phlegm-heat respiratory conditions for over two millennia. Preclinical evidence confirms anti-inflammatory and anti-asthmatic activity. No human RCTs exist.

• triphalaTraditional

  Triphala is documented in Ayurvedic texts for respiratory conditions including asthma, cough, and mucus-related disorders. Terminalia bellirica (Bibhitaki) has the strongest traditional application for respiratory support. Scientific evidence for respiratory endpoints in human subjects is absent.

• vasicinolTraditional

  Vasicinol is a pyrroquinazoline alkaloid from Adhatoda vasica (Vasaka), a plant with deep roots in Ayurvedic, Siddha, and Unani medicine for respiratory conditions including asthma, bronchitis, and cough. It is one of several co-occurring alkaloids (alongside vasicine and vasicinone) credited with bronchodilator and anti-allergic activity. Preclinical evidence supports these effects, but no human clinical trials have isolated vasicinol specifically to confirm efficacy in the respiratory system.

• wheat grassTraditional

  Wheatgrass is documented in traditional Ayurvedic and naturopathic medicine for respiratory conditions including asthma. Proposed mechanisms involve anti-inflammatory chlorophyll and antioxidant vitamins reducing airway inflammation. No human clinical trial has validated wheatgrass for respiratory outcomes.

• white oakTraditional

  White oak bark tea is traditionally used for respiratory conditions including colds, cough, bronchitis, and sore throat. Its expectorant, anti-inflammatory, and antimicrobial properties support this use. No clinical trials targeting the respiratory system have been conducted.

• wintergreenTraditional

  Native American tribes traditionally used wintergreen leaf teas for respiratory ailments including colds and flu, documented in ethnobotanical sources. In vitro antimicrobial activity against respiratory pathogens provides some mechanistic basis. No clinical respiratory trials on wintergreen exist.

• wood betonyTraditional

  Wood betony is documented in European folk herbalism and traditional Austrian medicine for respiratory tract conditions including bronchitis, asthma, coughs, and nasal congestion, attributed to its expectorant, anti-inflammatory, and decongestant properties.

• yellow rootTraditional

  Yellow Root has traditional documented use for respiratory ailments including colds, bronchial congestion, cough, and sinus conditions. It is classified alongside goldenseal as a mucous membrane herb applicable to the respiratory tract. Berberine's antimicrobial and anti-inflammatory properties provide mechanistic support.

• yuccaTraditional

  Yucca has an ethnobotanical record for respiratory use, specifically in the treatment of asthma. New Mexico folk healers brew yucca leaf tea for asthma and headaches, a use documented in multiple ethnobotanical records and the 2023 PMC phytochemical review. No clinical respiratory trial for yucca exists.

• zanthoxylumTraditional

  Respiratory applications of Zanthoxylum are documented in traditional medicine, particularly for asthma and respiratory spasms. Z. armatum and Z. caribaeum are ethnobotanically used for asthma. Antispasmodic and anti-inflammatory properties offer mechanistic plausibility. No respiratory clinical trials exist.