Linden

Linden (Tilia spp.): A Comprehensive Reference

1. Identity, Botanical Classification, and Common Preparations

1.1 Botanical Identity

Many medicinal species of linden exist, with Tilia cordata and Tilia platyphyllos generally being the most available and studied. The European Pharmacopoeia 9.0 defines lime flower as whole dry flowers obtained from Tilia platyphyllos Scop., Tilia cordata Mill., Tilia × vulgaris Hayne (syn. T. × europaea L.), or their mixture. Other species with documented traditional and pharmacological use include Tilia tomentosa Moench (silver linden), Tilia argentea, and Tilia americana (American linden or basswood). The European Pharmacopoeia 9.0 requires that valid plant material should not be contaminated with other commonly growing Tilia species such as Tilia tomentosa Moench.

Linden trees belong to the Tiliaceae family, which consists of nearly 80 species native to Europe and found in northern temperate regions. The five-petaled, fragrant, yellow to white flowers are collected after spring bloom, dried, and carefully preserved. Though sometimes called lime flower, linden is not related to the familiar green lime fruit. The pharmacopeial plant material — the dried inflorescence, including the associated bract — is officially designated Tiliae flos.

1.2 Nomenclature and Common Names

Scientific names in commerce include Tilia cordata Mill. and Tilia platyphyllos Scop. Common names include basswood, European linden, lime flower, lime tree, and linden. Tiliae flos, commonly known as lime flower or linden flower, is a popular plant material used in the form of an infusion.

1.3 Pharmacopoeial Status

Tiliae flos has a monograph in European Pharmacopoeia 9.0 (2016), and its description was also published by the European Medicines Agency (EMA) as a herbal traditional medicine (2011, 2012). The linden flower is listed in the German Pharmacopoeia and is approved in the German Commission E monographs. In Germany, it is included in common cold and antitussive preparations, as well as in urological and sedative drugs.

1.4 Plant Parts Used and Common Preparations

Regardless of species, the flowers are used as medicine. Linden flowers, leaves, wood, and charcoal (obtained from the wood) are the parts used for medicinal purposes. Tilia flowers are used worldwide in the form of infusions, decoctions, or tinctures. Essential oil produced from the flowers is a popular ingredient in perfumes and bath preparations.

2. Traditional and Historical Use

2.1 European Traditions

Since the Middle Ages, the flowers of the linden tree have been primarily used as a diaphoretic to promote sweating. Since time immemorial, the fragrant and tasty linden flowers have been used medicinally as a calming agent and to relieve indigestion, the common cold, and griping or colicky pain in the abdomen.

Early authors of herbal remedies recorded very little about the use of linden tree flowers. Records of their use first appear in the late Middle Ages. Hildegard von Bingen was among the first to appreciate a wider application of the linden tree, including its flowers.

Among the ancient Slavs, linden was considered a talisman against diseases and lightning; leaves were inscribed on log cabins and infusions were used for fever. The Slavs planted linden close to churches and homes — they believed lightning would not strike the linden tree, so people hid underneath it during thunderstorms.

In ancient Greece, the linden tree was considered a symbol of healers. Today, healers on the island of Crete recognize linden blossoms and linden tea among their oldest known remedies. The Greek name for the linden tree, "Philyra," derives from Crete, where the tree's flowering blossoms were prized for their healing properties.

2.2 Traditional Therapeutic Applications

Since the Middle Ages, the flowers of the linden tree have been primarily used as a diaphoretic to promote sweating. They have also been used for a variety of other medicinal purposes in phytotherapy, including as an expectorant, diuretic, antispasmodic, stomachic, and sedative. In addition, the flowers have been used traditionally for the treatment of flu, cough, migraine, nervous tension, indigestion, various types of spasms, liver and gallbladder disorders, diarrhea, and elevated arterial pressure associated with arteriosclerosis.

In German pediatric medicine, linden is included with several other species as a diaphoretic component in a tea used to treat influenza. The dried sapwood is consumed as a decoction as a drainer of the liver and kidneys, especially in cases of uric acid overload, renal or biliary lithiasis, and digestive spasms. Its charcoal has been used in medicine for the treatment of digestive problems and can also be used to sanitize burns.

Infusions of Tilia are widely used in traditional medicine in Europe and Latin America for the treatment of enterocolitis, gastroenteritis, and liver and renal colic, but mainly due to their tranquilizing activity.

3. Phytochemistry: Key Constituents and Active Compounds

3.1 Flavonoids

Flavonoids constitute the primary pharmacologically active class of compounds in linden flowers. The main constituents present in the linden flower include flavonoids — mainly quercetin (rutoside) and kaempferol glycosides (tiliroside, astragalin); condensed tannins (mainly procyanidins — dimeric, trimeric, tetrameric, and pentameric compounds); carbohydrates (arabinose, galactose, rhamnose, glucose, xylose, galacturonic and glucuronic acid); saponins; phenolic acids; mucilage (mainly galactomannans); and volatile oil (farnesol, geraniol, eugenol, nerol, α-pinene, limonene, terpenes, citral, citronellol).

Phytochemical studies have reported that flavonoids, such as quercitrin, isoquercitrin, kaempferol, astragalin, hyperoside, tiliroside, quercetin-3,7-O-dirhamnoside, and kaempferol-3,7-O-dirhamnoside, are major components of methanol extracts from the Tilia genus.

Ziaja et al. (2020) investigated the flavonoids in flowers of T. cordata, T. platyphyllos, T. × vulgaris, T. tomentosa, and T. americana, revealing isoquercitrin, astragalin, tiliroside, and protocatechuic acid as common compounds among them.

Kaempferol–3-O-β-D-(6″-p-coumaroyl)-glucopyranoside (tiliroside) was isolated for the first time from the leaves of Tilia argentea Desf. ex DC by Hörhammer et al. in 1961. It is a glycosidic flavonoid ester commonly found in nature in herbal plants and in medicines.

3.2 Volatile Oil

Volatile oil components (0.02% to 0.1%) include alkanes, esters, citral, eugenol, and limonene. Sedative properties may be associated with the volatile oil components citral, citronellal, citronellol, eugenol, and limonene. These effects were evident when mice inhaled oil from Tilia species.

3.3 Mucilage, Tannins, and Other Constituents

Active ingredients in linden flowers include quercetin, rutin, kaempferol, volatile oils, mucilage, and other flavonoids. The flavonoids and p-coumaric acid appear to be responsible for the diaphoretic and antispasmodic properties of the plant. Other constituents include caffeic and chlorogenic acids, as well as the amino acids alanine, cysteine, cystine, and phenylalanine. Carbohydrates, such as arabinose, galactose, glucose, mannose, and xylose, are also present in the plant, as well as gum and mucilage polysaccharides (3%).

3.4 Pharmacokinetics

An anxiolytic fraction of Tilia americana standardized in tiliroside, rutin, quercitrin, quercetin glucoside, and kaempferol was obtained. After oral administration of the fraction, these flavonoids were not detected in plasma over 24 hours. However, meta and para hydroxyphenylacetic acid and dihydroxyphenylacetic acid (m-HPAA, p-HPAA, and DOPAC) were monitored — these are biotransformation compounds of the aglycones of kaempferol and quercetin. No data on lime flower extract pharmacokinetics in humans have been found or reported.

4. Mechanisms of Action

4.1 Anxiolytic and Sedative Mechanisms

In a study by Viola et al., extracts of inflorescences from Tilia tomentosa Moench were purified using a benzodiazepine (BZD) binding assay to detect BZD receptor ligands in different fractions. One of the ligands was identified as kaempferol, but it had low affinity (K(i) = 93 μM) for this receptor and did not produce sedative or anxiolytic effects in mice. On the other hand, a complex fraction, containing yet unidentified constituents but probably of a flavonoid nature, when administered intraperitoneally in mice, had a clear anxiolytic effect in both the elevated plus-maze and hole board tests — two well-validated pharmacological tests. This active fraction had no effect on total and ambulatory locomotor activity.

In previous studies, significant and dose-dependent antinociceptive and anxiolytic-like activities were demonstrated after administration of hexane, methanol, and aqueous extracts of Tilia inflorescences (10–300 mg/kg), where glycosides of quercetin and kaempferol were characterized as the main active compounds of the inflorescences. Although it has been demonstrated that these metabolites might facilitate the inhibitory response of the central nervous system (CNS) by modulating the GABAergic and serotoninergic systems, it is unknown if these are the only possible mechanisms of action.

Several studies have reported the ability of Tilia tomentosa to induce sedative effects on the CNS, potentially through the interaction of their phenolic content — mainly represented by flavonol glycosides (quercetin, kaempferol, and apigenin derivatives) and phenolic acids — on GABAergic and serotoninergic pathways.

4.2 Diaphoretic and Antispasmodic Mechanisms

While flavonoids — mainly tiliroside — are attributed to be responsible for diaphoretic action, quercetin derivatives exhibit a weak diuretic effect. Among the present constituents in the linden flower, mucilage has a protective, antitussive, and soothing effect on the irritation of the throat mucosa and the gastrointestinal tract.

4.3 Anti-inflammatory Mechanisms

Two of the most active components, astragalin and its 6″-p-coumaryl ester (tiliroside), showed potent inhibitory effects on TNF-α production induced by LPS-challenging. The activity was suggested to depend on the inhibition of TNF-α production and decreased sensitivity to TNF-α.

All investigated Tilia species (T. cordata, T. platyphyllos, T. rubra, T. tomentosa) displayed remarkable antioxidant activity and significantly inhibited LPS-induced nitrite, IL-6, and PGE2 production in a 2025 in vitro study using RAW264.7 macrophage cells.

4.4 Hepatoprotective Mechanisms

By bioassay-guided separation using in vitro D-GalN-induced damage to hepatocytes, five flavonol glycosides were isolated as hepatoprotective constituents of the methanolic extract. Tiliroside, the principal flavonol glycoside, strongly inhibited serum GPT and GOT elevations at doses of 25–100 mg/kg (p.o.) in D-GalN/LPS-treated mice. By comparing the inhibitory effects of tiliroside with those of its components alone, the kaempferol 3-O-β-D-glucopyranoside moiety was found to be essential for the activity, and its effect was suggested to depend on the inhibition of TNF-alpha production, decreased sensitivity of hepatocytes to TNF-alpha, and on the protection of hepatocytes against D-GalN.

5. Scientific Evidence by Area of Use

5.1 Upper Respiratory Tract: Colds, Cough, and Fever

Tiliae flos is certified as a food product and as a medicine to treat the symptoms of the common cold, such as a sore throat, cough, and fever. The German Commission E has approved linden flower for the treatment of colds and cold-related coughs.

In traditional medicine, lime flowers are used in the form of an infusion for the treatment of feverish colds, catarrh, coughs, and influenza. Extracts from Tiliae flos are also used as diaphoretics, antispasmodics, and expectorants.

Strength of evidence: The Commission E approval rests substantially on traditional use and on pharmacological evidence for the mucilage-based demulcent and flavonoid-based diaphoretic mechanisms rather than on prospective randomized clinical trials. Formal human clinical trial data for the respiratory indication are sparse. The EMA classified linden flower for these uses under the category of "traditional herbal medicinal product."

5.2 Anxiety and Sleep

A complex fraction from Tilia tomentosa inflorescences, containing as yet unidentified constituents but probably of a flavonoid nature, when administered intraperitoneally in mice, had a clear anxiolytic effect in both the elevated plus-maze and hole board tests. This active fraction had no effect on total and ambulatory locomotor activity.

Another study documented that freeze-dried aqueous extracts of linden, at doses ranging from 10 to 100 mg/kg, produced sedative effects in mice. In another study, both the hexane and methanol extracts of Tilia americana var. mexicana demonstrated anxiolytic and sedative effects in mice.

One pilot human clinical study examined a multi-ingredient product. The pilot study investigated a supplement consisting of predetermined amounts of linden (Tilia tomentosa, 150 mg extract solid), hawthorn (C. oxyacantha, 150 mg extract solid), vitamin B1 (1.65 mg), and melatonin (1 mg) in the treatment of mild/moderate insomnia in 41 participants over four weeks. The open-label design may introduce bias in subjective outcomes, as participants and researchers are aware of the treatment being administered. The lack of blinding may influence participants' perceptions and expectations. Short study duration means longer-term effects cannot be captured.

Strength of evidence: Animal and in vitro data provide mechanistic plausibility for anxiolytic and sedative effects. The single human pilot study used a multi-ingredient combination with unblinded design, making it impossible to attribute effects to linden specifically. Although used as a traditional herbal remedy for anxiety, these results have not been confirmed in human clinical trials.

5.3 Gastrointestinal Conditions

Older clinical trials have shown that linden flower tea can help people with mild gallbladder problems (but not gallstones), upset stomach or dyspepsia, and excessive gas that causes the stomach to push up and put pressure on the heart (also known as gastrocardiac syndrome). Linden's reputed antispasmodic action, particularly in the intestines, has been confirmed in at least one human trial.

Quercetin and kaempferol from Tilia extracts were shown to exert beneficial effects in the gastrointestinal tract. Quercetin and kaempferol have been revealed to ameliorate GI function in the presence of IBS for their ability to inhibit LPS and NF-kB signaling, respectively. Moreover, administration of quercetin and kaempferol was shown to ameliorate gut microbiota composition affected by colitis or high-fat diet-induced obesity.

Strength of evidence: The antispasmodic confirmation in human trials comes from older, limited studies. The human microbiota evidence is ex vivo only. Mechanistic support is reasonably strong from in vitro and animal work, but large controlled human trials are lacking.

5.4 Anticonvulsant Activity

Anticonvulsant activity of Tilia americana var. mexicana inflorescences and leaves was investigated by evaluating organic and aqueous extracts (100, 300, and 600 mg/kg, i.p.) and some flavonoids in the pentylenetetrazole-induced seizures model in mice. Antioxidant effect of these extracts and flavonoids was also examined in vitro. Significant activity was observed in the methanol extract from inflorescences. These results provide evidence of the anticonvulsant activity of Tilia, reinforcing its utility for CNS diseases, with a mechanism of action that might involve partial antioxidant effects due to the presence of flavonoids.

Strength of evidence: Preclinical (animal model) only. No human clinical trials have investigated linden for seizure disorders.

5.5 Pain and Fibromyalgia

An aqueous Tilia extract (TE) and its flavonoid fraction (FF) containing rutin and isoquercitrin were evaluated alone and/or combined with clinical drugs (tramadol and pramipexole) using the reserpine-induced fibromyalgia model in rats. Chromatographic analysis allowed the characterization of flavonoids, while histological analysis confirmed their presence in the brain. TE (10–100 mg/kg, i.p.) and FF (10–300 mg/kg, i.p.) produced significant and dose-dependent antihyperalgesic and antiallodynic effects equivalent to tramadol (3–10 mg/kg) or pramipexole (0.01–1 mg/kg).

Strength of evidence: Preclinical (animal model) only. No human studies have been published on linden for pain syndromes.

5.6 Hepatoprotective Activity

One study was carried out to evaluate the hepatoprotective effect and antioxidant role of infusion prepared from linden flowers against ethanol-induced oxidative stress. The results indicated that the linden flower beverage extract could not be as important as diet-derived antioxidants in preventing oxidative damage in the tissues by reducing lipid oxidation or inhibiting the production of ethanol-induced free radicals in rats. In contrast, earlier work on Tilia argentea demonstrated hepatoprotective effects via tiliroside-mediated TNF-α suppression, as described in the mechanisms section above.

Histological, biochemical, and oxidative stress analyses for the evaluation of kidney and liver damage support the hypothesis that the linden extract is safe and well-tolerated under the present experimental conditions.

Strength of evidence: Rodent models only; results are mixed across studies and species. No human clinical trials on hepatoprotection have been published.

5.7 Anticancer Activity

A 2025 study investigated the anti-cancer effects of chemically characterized Tilia species on MIA PaCa-2 cells by analyzing oxidative stress and inflammation status. Extracts from the flowers, bracts, and inflorescences of T. cordata, T. platyphyllos, T. rubra, and T. tomentosa were evaluated for antioxidant activity; subsequently, their ability to mitigate inflammation was assessed through in vitro nitrite assays in LPS-induced RAW264.7 cells. The anticancer potentials were investigated in 2D (cytotoxic effect) and 3D (effect on spheroid growth) models in vitro. Extract from T. rubra bracts showed the highest cytotoxic activity against MIA PaCa-2 cells with an IC50 value of 0.16 mg/mL.

Astragalin and tiliroside, which were initially isolated from the leaves of T. tomentosa, are responsible for various pharmacological activities of Tilia species, including antioxidant, anti-inflammatory, hepatoprotective, neuroprotective, antithrombotic, antidiabetic, antiobesity, antiviral, antiosteoporotic, and antiproliferative activities.

Strength of evidence: In vitro cell-line data only. No human trials exist. These findings should be considered highly preliminary.

5.8 Gut Microbiota

A 2022 study published in the Journal of Ethnopharmacology investigated the effect of Tiliae flos metabolites on human gut microbiota biodiversity using an ex vivo model. The main constituents present in linden flower — flavonoids (mainly quercetin and kaempferol glycosides), condensed tannins (procyanidins), and other polyphenols — were characterized as the substrates driving microbial biotransformation.

Strength of evidence: Ex vivo (lab-based fermentation with human fecal microbiota) only. Clinical data are absent.

6. Body Systems and Health Areas Associated with Linden

• Nervous system: Anxiolytic, sedative, and antispasmodic effects, primarily demonstrated in animal models; interaction with GABAergic and serotoninergic pathways proposed.
• Respiratory system: Demulcent action on mucous membranes (mucilage), diaphoretic action (flavonoids), antitussive properties; Commission E–approved for cold-related cough.
• Gastrointestinal system: Antispasmodic effect on intestinal smooth muscle, mild diuretic effect from quercetin derivatives, demulcent action on GI mucosa.
• Cardiovascular system: Historical use for hypertension and nervous palpitations; linden has been used to induce sweating for feverish colds and infections, reduce nasal congestion, relieve throat irritation and cough, and has sedative effects used to treat nervous palpitations and high blood pressure.
• Hepatic system: In vitro and animal hepatoprotection linked to tiliroside and astragalin via TNF-α inhibition.
• Skin: Reports exist of specific toxicity including contact urticaria; topical use has also been described for itchy skin.

7. Dosage Forms and Reported Dosages

Linden is available in several dosage forms. There are no recent clinical studies to support a specific dosage of linden. No more than 2 to 4 g/day of linden from teas or other preparations for internal use should be consumed.

Tea infusion: drink a cup of linden tea as hot as possible (sweating cure), 2 to 4 times daily with an average daily dose of 2–4 grams. Preparation involves pouring 150 mL of boiling water over 1 to 2 g of lime blossom and straining after 5–10 minutes.

A tea of linden is prepared by adding 2–3 teaspoons (5–10 grams) of dried or fresh flowers to a pint (500 mL) of just-boiled water. After steeping the flowers in a covered container for ten to fifteen minutes, the tea is sipped while still hot. During an acute problem, several cups can be taken daily for up to one week. For longer-term use (three to six months), three cups (750 mL) per day can be used.

In the multi-ingredient pilot sleep study, participants received a food supplement based on linden (Tilia tomentosa, 150 mg extract solid), hawthorn (C. oxyacantha, 150 mg extract solid), vitamin B1 (1.65 mg, 150% VNR), and melatonin (1 mg).

In animal anxiolytic studies, significant and dose-dependent activities were demonstrated after administration of Tilia inflorescence extracts at 10–300 mg/kg in mice. These animal dosages are not directly translatable to human use.

8. Safety Considerations and Known Interactions

8.1 General Safety Status

Both the German Commission E monograph and the American Herbal Products Association's guide on herbal safety state that linden has no toxic effects. In fact, linden is considered safe for use in children and there are no known reasons to avoid it during pregnancy and breastfeeding.

Histological, biochemical, and oxidative stress analyses for the evaluation of kidney and liver damage support the hypothesis that the linden extract is safe and well-tolerated based on the available preclinical data.

8.2 Cardiovascular Concerns

The German Commission E monograph concluded that the linden flower is cardiotoxic; therefore, linden should not be consumed by patients with a history of heart disease. However, statements that overuse of linden can cause heart problems lack scientific merit. Frequent use of linden flower teas has been associated with heart damage occurring in rare cases. There is a clear tension in the literature between the Commission E's cardiotoxicity note and other authoritative sources that find no evidence of toxicity; this conflict has not been resolved by prospective data.

8.3 Allergic Reactions

Reports exist of specific toxicity such as contact urticaria, allergy from Tilia fruit oils in rats, seasonal pollinosis, pesticide residues in linden-containing beverages, and contact dermatitis and rhinoconjunctivitis from exposure to linden wood sawdust in the workplace. Occupational contact dermatitis with rhinoconjunctivitis due to T. cordata and colophonium exposure in a cosmetician has been reported. Contact urticaria has been reported. No allergens from this plant have yet been characterised. Cross-reactivity among the different species of the genus could be expected.

8.4 Infant Botulism Risk

In many countries, people use linden flower tea as a household remedy and give it to infants as a sedative. In a study analyzing 100 samples of unwrapped linden flowers and 100 samples of linden flowers in tea bags, results showed a prevalence of 3% of botulinum spores in the unwrapped linden flowers analyzed, with a spore load of 30 spores per 100 grams. None of the industrialized linden flowers in tea bags were contaminated with botulinum spores. Linden flowers must be considered a potential vehicle of C. botulinum, and the ingestion of linden flower tea can represent a risk factor for infant botulism.

8.5 Species Adulteration

There is a risk of adulteration with other Tilia species (e.g., Tilia tomentosa), which may have different phytochemical profiles, or with other plant materials. The European Pharmacopoeia 9.0 requires that the valid plant material should not be contaminated with other commonly growing Tilia species such as Tilia tomentosa Moench.

8.6 Drug Interactions

A number of actions have been associated with volatile oils including diuretic, sedative, and antispasmodic effects in mice, which may account for some of the reputed uses of lime flower. Because of the demonstrated sedative properties in animal models and the mechanistic interaction with GABAergic pathways, additive effects with CNS depressants are biologically plausible, though not confirmed in human pharmacokinetic studies. There is limited clinical information on drug-herb interactions with linden specifically.

References

• European Medicines Agency (EMA) — Final Assessment Report on Tilia cordata Miller, Tilia platyphyllos Scop., Tilia × vulgaris Heyne or their mixtures, flos (First Version)
• European Medicines Agency (EMA) — Final Assessment Report on Tilia tomentosa Moench, flos
• European Medicines Agency (EMA) — Tiliae flos Herbal Medicinal Product Page
• Matsuda et al. — Hepatoprotective principles from the flowers of Tilia argentea (linden): structure requirements of tiliroside and mechanisms of action. PubMed (2002)
• PubMed — Hepatoprotective and antioxidant activity of linden (Tilia platyphyllos L.) infusion against ethanol-induced oxidative stress in rats (2014)
• PubMed — Toxicological and anti-tumor effects of a linden extract (Tilia platyphyllos Scop.) in a HPV16-transgenic mouse model (2021)
• PubMed — Linden flower (Tilia spp.) as potential vehicle of Clostridium botulinum spores in the transmission of infant botulism (2010)
• PMC — Anticonvulsant and Antioxidant Effects of Tilia americana var. mexicana and Flavonoids Constituents in the Pentylenetetrazole-Induced Seizures
• PMC — Pharmacokinetic Study of Biotransformation Products from an Anxiolytic Fraction of Tilia americana
• PMC — Pharmacological Interaction of Quercetin Derivatives of Tilia americana and Clinical Drugs in Experimental Fibromyalgia
• PMC — Enhancing Sleep Quality: Assessing the Efficacy of a Fixed Combination of Linden, Hawthorn, Vitamin B1, and Melatonin
• PMC — Influence of Tilia tomentosa Moench Extract on Mouse Small Intestine Neuromuscular Contractility
• PMC — Spray-drying Microencapsulation of an Extract from Tilia tomentosa Moench Flowers
• PMC — Optimization of Extraction Conditions for Determination of Tiliroside in Tilia L. Flowers Using an LC-ESI-MS/MS Method
• PMC — Tilia species (linden) exert anti-cancer effects on MIA PaCa-2 cells through the modulation of oxidative stress and inflammation
• ScienceDirect — Tiliae flos metabolites and their beneficial influence on human gut microbiota biodiversity ex vivo. Journal of Ethnopharmacology (2022)
• ScienceDirect — UHPLC-DAD-MS/MS analysis of extracts from linden flowers (Tiliae flos): Differences in the chemical composition between five Tilia species growing in Europe
• ScienceDirect — Flavonoids with antinociceptive and anti-inflammatory activities from the leaves of Tilia argentea (silver linden). Journal of Ethnopharmacology (2004)
• Drugs.com — Linden Uses, Benefits & Dosage (medically reviewed, last updated Dec 2025)
• PeaceHealth Medical Topics — Linden Health Information Library
• Thermo Fisher Scientific — Allergen Encyclopedia: t208 Linden
• PubMed — Allergy to linden pollen (Tilia cordata). Allergy (2001)
• American Botanical Council — Expanded Commission E: Linden Flower
• Arzneipflanzenlexikon — Linden: Medicinal Use, Dosage, Side Effects, Interactions