Rumex acetosa

Rumex acetosa (Common Sorrel): A Comprehensive Reference

1. Identity: Botanical Classification, Nomenclature, and Natural Source

Scientific name: Rumex acetosa L. The species epithet acetosa derives from the Latin word acetum, meaning vinegar, describing the taste of the plant as vinegar. The genus name Rumex has two proposed etymological origins: the name "Rumex" originated from the Greek word meaning "dart" or "spear," alluding to the shape of leaves, while another explanation from Rome — "rums" — alludes to the function that the leaves could be sucked to alleviate thirst.

Common names: Rumex acetosa is commonly referred to as sorrel, common sorrel, garden sorrel, spinach dock, acid sorrel, and cigreto, among many other regional names around the world.

Taxonomic classification: Rumex acetosa, commonly known as common sorrel, is an herbaceous perennial plant that grows to about 1 meter in height, characterized by its large, fleshy, green leaves with pointed basal lobes and greenish flowers. The species belongs to the family Polygonaceae and is distributed worldwide, including African, Asian, American, and European countries.

Botanical nature and habitat: Sorrel has been utilized as a wild-gathered plant for thousands of years and as a cultivated plant for centuries. Primarily roots, but also other tissues, have been used in folk remedies since ancient times. As a cultivated plant, sorrel, R. acetosa, has been produced for centuries, and it is a quite widely used herb in native cuisine throughout Europe and parts of Asia, such as India and Vietnam, and parts of Africa, such as Ethiopia and Cameroon, where it is grown as a garden herb or vegetable.

Parts used: The leaves and aerial parts are most commonly used as food and medicine. The roots and seeds also have documented medicinal uses across traditions. R. acetosa L. is a wild perennial plant, well known for the presence of many biologically active phytoconstituents. All parts of the plant, including the leaves, are important sources of various therapeutic constituents.

Common forms and preparations: In some regions, the leaves of R. acetosa are utilised as foods, mainly in the forms of sour soups (usually in milk), sauces, and salads. As a medicinal preparation, the plant is used as a hydroethanolic or methanolic extract, a dry powdered extract, a decoction of roots or leaves, an infusion of aerial parts, a juice of fresh leaves, and — in modern European phytotherapy — as a standardized dry extract incorporated into registered combination herbal products. R. acetosa is officially listed in the Korean Food Code (Korea Food & Drug Administration) as one of the main food materials and has been used in folk medicine as a mild purgative and also for the treatment of cutaneous diseases.

Nomenclature note: Rumex acetosa should not be confused with the closely related Rumex acetosella (sheep's sorrel) or with unrelated species sometimes sold as "sorrel," such as Hibiscus sabdariffa (Jamaican sorrel/roselle) or Oxalis spp. (wood sorrel). These are botanically and chemically distinct plants.

2. Traditional and Historical Use

The genus Rumex with more than 200 species is distributed widely in the world and has been used traditionally in many regions, including Asia, America, Europe, and other continents. Many of them known as "sorrel" or "dock" have a long history of food application and medicinal uses for the treatment of skin diseases and hemostasis after trauma by the local people of their growing areas.

Europe (Britain and Ireland): In Britain and Ireland, R. acetosa is used for the treatment of scurvy, wounds, warts, bruises, jaundice, and sore throat. The roots of many species belonging to the genus Rumex have been used in medicine from ancient times because of their gentle laxative effect.

Eastern Europe and Hungary: In historical records from Romania and Eastern Europe, Rumex species have been used for constipation, diarrhoea, kidney disorders, swellings, sores, rashes and wounds, ringworm, and as an astringent.

India and South Asia: Indians have also recorded nine Rumex plants as astringent agents, including R. acetosa. The aerial parts, leaves, and roots of the plants are used as vegetables and for the treatment of several health disorders such as mild diabetes, constipation, infections, diarrhoea, oedema, jaundice, and as an antihypertensive, diuretic, and analgesic, and in cases of skin, liver, and gallbladder disorders, and inflammation.

Korea and East Asia: R. acetosa (Polygonaceae) is recognized as a Korean and Japanese medicinal plant. It is officially listed in the Korean Food Code (Korea Food & Drug Administration) as one of the main food materials and has been used in folk medicine as a mild purgative and also for the treatment of cutaneous diseases.

China: All seven species, including R. acetosa, R. trisetifer, R. patientia, R. crispus, R. japonicus, R. dentatus, and R. nepalensis, called "jinbuhuan," have been used for hemostasis remediation in China.

Global diuretic use: R. acetosa is commonly used medicinally for diuretics around the world.

Gastrointestinal uses: Across multiple traditions, the plant has been employed to manage constipation and diarrhea. Many cultures around the world use the leaves and aerial parts as vegetables; other parts of this medicinal plant are employed in the management of a number of ailments such as constipation, diarrhea, jaundice, mild diabetes, and as an analgesic, antihypertensive, against gallbladder, liver, and skin disorders, and inflammation.

Europe — registered therapeutic product: Modern phytotherapeutical preparations with nationally registered drug status in Europe contain extracts from R. acetosa for treatment of acute and chronic infections of the upper respiratory system. Since 1934, the herbal preparation Sinupret has been used to repair and maintain the physiological activity of the mucosa in the paranasal sinuses in both liquid and sugar-coated tablet form.

3. Key Constituents and Active Compounds

The phytochemistry of this wild vegetable showed that over 60 compounds were reportedly isolated; these include anthraquinones, naphthalene, polyphenols, and other compounds. Many phytochemical investigations on this genus confirmed that Rumex species are rich in anthraquinones, naphthalenes, flavonoids, stilbenoids, triterpenes, carotenoids, and phenolic acids. Phenolics and polyphenols account for two-thirds of the over 70 isolated compounds from R. acetosa.

3.1 Flavonoids

The aerial parts have been reported to contain flavonoids including rutin, hyperoside, quercitrin, quercetin-3-O-glucuronide, avicularin, vitexin, orientin, isoorientin, and their acetyl derivatives. The herb is also a source of flavonoids such as hyperoside and quercetin glycosides. The flavonoid profile indicates that the subgenus Acetosa (to which R. acetosa belongs) is characterized by the predominance of C-glycosides.

3.2 Anthraquinones and Their Derivatives

Anthraquinones and their derivatives are one of the most abundant compound classes in Rumex species; they are present particularly in the roots. The aerial parts also contain 1,8-dihydroxyanthraquinones including chrysophanol and its 8-O-glucoside, physcion, physcionanthrone, emodin and its 8-O-glucoside, emodinanthrone, aloeemodin, and acetoxyaloeemodin. Anthranoid derivatives — emodin, chrysophanol, physcion, aloe-emodin, rhein, barbaloin, palmatin, and sennosides A and B — have been analysed in methanolic extracts of R. acetosa roots, leaves, and fruits by RP-HPLC.

3.3 Proanthocyanidins and Flavan-3-ols

The aerial parts contain flavan-3-ols including catechin and epicatechin. Recent phytochemical investigation of extracts has confirmed the presence of monomeric flavan-3-ols (catechin, epicatechin, epicatechin-3-O-gallate) as well as A- and B-type proanthocyanidins. These oligomeric and polymeric proanthocyanidins are of particular pharmacological relevance to the antiviral activity of the species (see Section 5.2).

3.4 Phenolic Acids

The aerial parts contain phenolic acids including gallic acid, protocatechuic acid, ferulic acid, and p-coumaric acid. The main phenolic compounds present in R. acetosa include trans- and cis-resveratrol (41.27 μg/g), vanillic acid (130.29 μg/g), sinapic acid (5708.48 μg/g), and catechin (75.46 μg/g).

3.5 Oxalic Acid

The plant is noted for its acidic-tasting leaves and high levels of oxalic acid. Cooking reduces oxalic acid concentration to negligible amounts. Oxalic acid is responsible for the characteristic sour taste but is also the primary safety concern at high intakes (see Section 7).

3.6 Tannins and Polysaccharides

The aerial parts contain higher amounts of polysaccharides from the rhamnogalacturonan and arabinogalactan type with immunostimulating and antiphlogistic properties. The concentration of tannins in R. acetosa's leaves is between 8 and 16%. A polysaccharide designated RA-P has been isolated from the root: this polysaccharide (RA-P) has a 30 kDa molecular weight and consists of D-glucose and D-arabinose.

3.7 Additional Phytochemicals

The aqueous ethanol extract of R. acetosa contains alkaloids, carbohydrates, glycosides, tannins, phytosterols, proteins, amino acids, flavonoids, and anthocyanins. Stilbenes, including resveratrol, have been identified alongside naphthalene derivatives and triterpenes in phytochemical screenings of the genus.

4. Established and Proposed Mechanisms of Action

Pharmacological studies on Rumex extracts and its pure components have revealed a wide range of bioactivities, involving antimicrobial, anti-inflammatory, antiviral, renal and gastrointestinal protective effects, antioxidant, antitumor, and anti-diabetes effects. The principal mechanisms associated with the plant's observed bioactivities are described below.

4.1 Anti-inflammatory Mechanisms

In LPS-induced RAW 264.7 macrophage cells, the methylene chloride fraction of R. acetosa showed the strongest reducing effect on nitric oxide production. In addition, this fraction suppressed the phosphorylation of ERK and JNK, and the expression of cyclooxygenase-2 (COX-2) in a dose-dependent manner. The herbal medicinal product containing R. acetosa (Sinupret/BNO 1016) exerts significant oral anti-inflammatory effects by a reduction of cyclooxygenase (COX)-2 expression and prostaglandin (PG)E2 formation. Anti-inflammatory activity involves emodin and other constituents that downregulate interleukins, TNF-α, and COX enzymes.

4.2 Antioxidant Mechanisms

Antioxidant effects, driven by flavonoids and polyphenols, include free radical scavenging and reduction of oxidative stress. Five fractions of R. acetosa total ethanolic extract were studied for antioxidant activity; the ethyl acetate fraction contained the highest total phenol and flavonoid contents among the five fractions and exhibited the most potent antioxidant activity. It was found that the 80% methanol extract of the roots (IC50 = 118.8 μM) showed higher scavenging activity to DPPH free radicals than extracts from other parts of the plant.

4.3 Antiviral Mechanisms

Antiviral activity is linked to proanthocyanidins and involves suppression of viral replication. More specifically, the mechanism against herpes simplex virus and influenza A involves blocking viral attachment to host cell receptors: the dimeric proanthocyanidin procyanidin B2-di-gallate blocked attachment of influenza A virus (IAV) and interfered with viral penetration at higher concentrations. Galloylation of the procyanidin core structure was shown to be a prerequisite for anti-IAV activity.

4.4 Antimicrobial Mechanisms

Antibacterial activity includes antibiofilm effects mediated by compounds such as gallic acid, emodin, flavonoids, phenolics, tannins, and terpenes. Antifungal effects are primarily attributed to anthraquinones and involve inhibition of fungal germination, increased membrane permeability, and biofilm disruption.

4.5 Antiplatelet and Cardiovascular Mechanisms

The extract of R. acetosa inhibited collagen-induced platelet aggregation by regulating the phosphorylation of signaling pathways such as MAPK, PI3K/Akt, and Src family kinases, and reduced ATP release in a dose-dependent manner. Previous reports have suggested that the methanolic extract of R. acetosa contains catechin, epicatechin, and epigallocatechin-3-O-gallate, and these compounds have been known for their antiplatelet activities. Therefore, antiplatelet effects observed in studies could be attributed to catechin and epicatechin contained in R. acetosa extract.

4.6 Gastrointestinal Mechanisms

In rabbit jejunum preparations, methanolic extract of R. acetosa (0.01–1.0 mg/mL) caused a transient spasmogenic effect, followed by a spasmolytic effect (3–10 mg/mL). In the presence of atropine, the spasmogenic effect was blocked while the spasmolytic effect emerged, suggesting that the spasmogenic effect was mediated through activation of muscarinic receptors. This dual action provides a pharmacological basis for the traditional uses in both constipation (spasmolytic/laxative at higher concentrations) and diarrhea (tannin-mediated astringency).

5. Scientific Evidence by Area of Use

5.1 Upper Respiratory Tract Infections and Sinusitis

The strongest body of clinical evidence for R. acetosa concerns its use in a standardized five-herb combination product. Species of the genus Rumex have been studied in diverse clinical contexts. R. acetosa is included as one of the five herbal components in the fixed combination extract BNO 1016 (Sinupret, Bionorica SE, Germany), developed for the treatment of sinusitis. BNO 1016 (Sinupret® extract) comprises a dry extract of gentian root (Gentiana lutea L.), primula flower (Primula veris L.), sorrel herb (Rumex spp.), elder flower (Sambucus nigra L.), and verbena herb (Verbena officinalis L.).

Mechanism in the formulation: Rumicis herba (sorrel herb) is the source of flavonoids, including hyperoside and quercetin glycosides, and contributes antioxidant and anti-inflammatory activity relevant to mucosal inflammation. BNO 1016 has well-documented mucosecretolytic, secretomotoric, anti-inflammatory, and antiviral effects in vitro and in vivo.

Acute viral rhinosinusitis — Phase IIb/III RCT: Preclinical studies demonstrated antimicrobial, antiviral, anti-inflammatory, and secretolytic properties of the formulation. A Phase IIb/III clinical trial identified 160 mg administered three times daily as the optimal dose. This dosage was found to be effective and well tolerated over a 15-day treatment period in patients with acute viral rhinosinusitis. Daily intake of 480 mg of BNO 1016 for 15 days is an effective treatment in acute viral rhinosinusitis. The pooled efficacy data of two similar randomized placebo-controlled clinical trials were analysed.

Acute sinusitis symptom outcomes: Jund et al. showed a greater decrease in acute viral sinusitis symptoms (major symptom score decrease) with Sinupret treatment than with the placebo-treated group (p<0.0001).

Chronic rhinosinusitis — RCT (CRS-02): The objective of clinical trial CRS-02 was to assess the efficacy, safety, and tolerability of two dosages of BNO 1016 in patients with chronic rhinosinusitis (CRS). A total of 929 patients suffering from CRS were enrolled in this randomised placebo-controlled trial with a treatment period of 12 weeks. Sinupret extract was not superior over placebo regarding the primary endpoint. However, the results of secondary endpoints showed a clear trend towards superior efficacy. Post-hoc sensitivity analyses in patients with a baseline major symptom score over 9 and persistence of disease for more than 1 year found that those patients significantly benefited from Sinupret extract. A good safety and tolerability of Sinupret extract was assured in all patients. Sinupret extract can safely be administered in patients with CRS.

Evidence characterization: The clinical evidence for BNO 1016 in acute viral rhinosinusitis is moderate to good, supported by multiple randomized controlled trials and a pooled analysis. However, because R. acetosa is only one of five components in BNO 1016, it is not possible to attribute clinical effects specifically to R. acetosa alone. No clinical trials have been conducted using isolated R. acetosa extracts for sinusitis. In chronic rhinosinusitis, the primary endpoint of the largest RCT was not met, limiting the evidence base.

5.2 Antiviral Activity (HSV-1 and Influenza A)

The polyphenol-enriched acetone–water extract (R2) from the aerial parts of Rumex acetosa L., containing high amounts of oligomeric and polymeric proanthocyanidins and flavonoids, was tested for antiviral activity. R2 exhibited strong antiviral activity against herpes simplex virus type-1 (HSV-1), while the replication of adenovirus 3 was not affected. By plaque reduction test and MTT assay on Vero cells, the HSV-1-specific inhibitory concentration (IC50) and cytotoxic concentration (CC50) were determined. R2 exhibited an IC50 of 0.8 μg/mL and a selectivity index (SI) of approximately 100 when added to the virus inoculum for 1 hour at 37°C prior to infection. The antiviral activity was due to the presence of flavan-3-ols and oligomeric proanthocyanidins in the extract. Structure–activity analyses indicated that flavan-3-ols and proanthocyanidins with galloylation at position O-3 are highly potent compounds (SI > 40), while ungalloylated compounds did not exhibit antiviral activity.

Against influenza A virus (IAV): A study characterizing the anti-IAV potential of the proanthocyanidin-enriched extract derived from the aerial parts of Rumex acetosa found that the extract inhibited growth of the IAV strain PR8 (H1N1) and a clinical isolate of IAV(H1N1)pdm09 with IC50 values of 2.5 μg/mL and 2.2 μg/mL, and a selectivity index of 32 and 36, respectively. The extract was also active against an oseltamivir-resistant isolate of IAV(H1N1)pdm09. The dimeric proanthocyanidin epicatechin-3-O-gallate-(4β→8)-epicatechin-3′-O-gallate (procyanidin B2-di-gallate) was identified as the main active principle of the extract (IC50 approximately 15 μM, SI ≥ 13).

Evidence characterization: This evidence is entirely in vitro (cell culture and mechanistic studies). There are no clinical trials evaluating R. acetosa extracts for HSV-1 or influenza in humans. The data are preliminary but mechanistically well-characterized.

5.3 Antibacterial Activity, Including Helicobacter pylori

Anti-Helicobacter pylori activity was observed in extracts of R. acetosa, where six anthraquinones exhibited MIC values between 3.13 and 25 μM. These compounds, including emodin and chrysophanol glucosides, also showed urease inhibitory effects, suggesting their potential for managing H. pylori-related gastric infections. Six major compounds were isolated from the methylene chloride and ethyl acetate fractions of Rumex acetosa that showed anti-H. pylori activity; these were identified as emodin, chrysophanol, physcion, emodin-8-O-β-D-glucoside, chrysophanol-8-O-β-D-glucoside, and physcion-8-O-β-D-glucoside by UV, 1H NMR, 13C NMR, and mass spectrometry.

Research on Rumex species from the Carpathian Basin revealed strong antibacterial activity, especially in the n-hexane and chloroform fractions of roots from R. acetosa, with inhibition zones >15 mm.

Evidence characterization: All antibacterial evidence is in vitro. No clinical trials have evaluated R. acetosa preparations against bacterial infections in humans. Evidence is preliminary.

5.4 Antioxidant Activity

In a study identifying antioxidant and anti-inflammatory activities, five fractions of n-hexane, methylene chloride, ethyl acetate, n-butanol, and aqueous fractions were obtained from the total ethanolic extract from whole parts of R. acetosa. The ethyl acetate fraction contained the highest total phenol and flavonoid contents among the five fractions and exhibited the most potent antioxidant activity.

Evidence characterization: Antioxidant evidence is in vitro. No controlled clinical trials in humans have evaluated antioxidant endpoints specifically for R. acetosa preparations.

5.5 Antiplatelet and Cardiovascular Effects

In laboratory studies using rat platelets, R. acetosa extract markedly inhibited collagen-induced platelet aggregation and ATP release in a dose-dependent manner. The data suggest that R. acetosa extract exhibits anti-platelet activity via modulating MAPK, PI3K/Akt pathways, and integrin αIIbβ3-mediated inside-out and outside-in signaling, and it may protect against the development of platelet-related cardiovascular diseases.

In animal models of blood pressure: Intravenous administration of the methanolic extract from R. acetosa leaves at 50 mg/kg led to a reduction in mean arterial pressure by 27.9% ± 4.6% in normotensive rats, and by 48.4% ± 4.9% in hypertensive rats.

Evidence characterization: All cardiovascular evidence derives from in vitro cell/platelet studies and animal experiments. No human clinical trials have been conducted. Evidence is preliminary.

5.6 Cytotoxic and Antimutagenic Activity

Four anthraquinones isolated for the first time from the aerial parts of Rumex acetosa, and two synthetic derivatives, were examined for their cytotoxicities against five cultured human tumor cell lines — A549 (non-small cell lung), SK-OV-3 (ovary), SK-MEL-2 (melanoma), XF498 (central nervous system), and HCY15 (colon) — using the Sulforhodamine-B method in vitro, and antimutagenic activities by Ames test with Salmonella typhimurium TA98 and TA100 and SOS chromotest with E. coli PQ37. Among the tested compounds, emodin strongly inhibited the proliferation of each examined tumor cell line with IC50 values ranging from 2.94 to 3.64 μg/mL and showed potent antimutagenic activities with 71.5% and 53.3% at the concentration of 0.1 mg/plate against the mutagens NPD and sodium azide, respectively.

Evidence characterization: All evidence for cytotoxic and antimutagenic activity is in vitro. These findings do not constitute clinical evidence for anti-cancer efficacy. No human trials exist.

5.7 Gastrointestinal Effects

Rumex acetosa is a folk medicine for gastritis and gastric ulcers. The ethanol extract of R. acetosa inhibited gastric ulcers and protected gastric tissue in mice induced with HCl/ethanol from gastric ulcers. The dual spasmogenic/spasmolytic mechanism described in Section 4.6 provides preclinical mechanistic support for traditional uses in gut motility disorders.

Evidence characterization: Gastrointestinal evidence is in vitro and in animal models (mice, rabbit jejunum). No controlled human clinical trials exist for these indications.

5.8 Oral Health (Periodontal)

Proanthocyanidin-enriched extract from the aqueous fraction of the acetone–water (7:3) extract of the aerial parts of R. acetosa (5–15 μg/mL) could interfere with the adhesion of Porphyromonas gingivalis — a key periodontal pathogen. Scientific evidence has been presented against oral diseases from isolated compounds of R. acetosa.

Evidence characterization: Evidence is in vitro. No clinical dental trials involving R. acetosa extracts as a standalone intervention have been identified.

6. Body Systems and Health Areas Associated With Rumex acetosa

• Upper respiratory tract: Anti-sinusitis use in registered five-herb combination BNO 1016; secretolytic, anti-inflammatory, and antiviral mechanisms.
• Immune system: Polysaccharides from the rhamnogalacturonan and arabinogalactan type have immunostimulating and antiphlogistic properties.
• Gastrointestinal system: Traditional laxative, antidiarrheal, astringent, and anti-ulcer uses supported by animal and in vitro evidence.
• Cardiovascular system: Antiplatelet and antihypertensive effects demonstrated in animal models.
• Integumentary system (skin): Traditional applications for wounds, rashes, and skin disorders; antioxidant and anti-inflammatory compounds relevant.
• Oral cavity: Anti-adhesion effects against periodontal pathogens in vitro.
• Renal and urinary system: Traditional diuretic use; also source of safety concerns due to oxalate content (see Section 7).
• Hepatic/biliary: Traditional use in jaundice and liver/gallbladder disorders; hepatoprotective activity linked to polyphenols in the genus. Hepatoprotective effects are mediated by flavonoids and polyphenols, resulting in reduced hepatotoxicity and improved antioxidant enzyme activity.

7. Dosage Forms and Dosages Reported in Studies

There are no standardized standalone dosages established for isolated Rumex acetosa preparations as a dietary supplement or herbal medicinal product. Dosages that have been reported in the scientific literature are as follows:

• BNO 1016 (Sinupret extract, containing R. acetosa as one of five components): Daily intake of 480 mg of BNO 1016 for 15 days was the dosage identified as effective in acute viral rhinosinusitis. A Phase IIb/III clinical trial identified 160 mg administered three times daily as the optimal dose. The chronic rhinosinusitis trial evaluated two dosages of BNO 1016 over a treatment period of 12 weeks in 929 patients.
• Methanolic extract of leaves (animal): Intravenous administration of the methanolic extract from R. acetosa leaves at 50 mg/kg produced antihypertensive effects in rats. This is an intravenous animal study dose and is not transferable to human oral supplementation.
• In vitro antiviral extract (R2): The proanthocyanidin-enriched extract exhibited an IC50 of 0.8 μg/mL against HSV-1.
• In vitro anti-influenza extract: IC50 values of 2.5 μg/mL and 2.2 μg/mL against IAV strains.
• In vitro anti-H. pylori anthraquinones: MIC values between 3.13 and 25 μM.
• Gut motility (ex vivo rabbit jejunum): Methanolic extract at 0.01–1.0 mg/mL caused a transient spasmogenic effect, followed by spasmolytic effect at 3–10 mg/mL.

No established human oral dosages for standalone R. acetosa preparations as a dietary supplement can be verified from the reviewed literature. Dosing information is confined to preclinical models and the multi-herb BNO 1016 formula.

8. Safety Considerations and Notable Interactions

8.1 Oxalic Acid Toxicity

Rumex plants contain notable amounts of oxalic acid, which can cause health issues when ingested in large quantities. High dietary oxalate intake is associated with secondary hyperoxaluria and an increased risk of calcium oxalate kidney stones. Oxalic acid in large amounts has many disadvantages, including its ability to bind micronutrients such as iron and calcium, thereby decreasing their absorption; oxalates irritate the digestive system when consumed in large amounts; and oxalic acid, when combined with calcium, forms crystallized calcium oxalate, which in the human system can lead to the formation of kidney stones and may also accumulate in the heart, circulatory vessels, and lungs.

The estimated lethal dose of oxalic acid in adults ranges from 15 to 30 g, with lower doses (<5 g) sometimes causing fatal outcomes. A case of acute toxicity from high-quantity raw sorrel consumption has been documented: in Turkey in 2015, a child was hospitalized after a day of eating large amounts of raw sorrel (Rumex acetosa), but fortunately made a full recovery. The clinical report was published in Clinical Toxicology (2015) as a case of acute tubulointerstitial nephritis.

Fortunately, light cooking greatly decreases oxalic acid concentration to negligible amounts.

8.2 Contraindications and Populations at Elevated Risk

Rumex consumption should be avoided by individuals with kidney stones, gout, arthritis, rheumatism, or hyperacidity. This wild vegetable "sorrel" may weaken the assimilation of both calcium and iron; patients with kidney stones, people affected by renal and arthritic conditions, as well as those with gastrointestinal disorders, may be especially vulnerable. The concentration of tannins in R. acetosa's leaves is between 8 and 16%, and care should be taken in consuming its fresh leaves in large amounts — especially for children, pregnant women, and older people — since tannins may cause stomach upset and/or kidney and liver damage.

8.3 Drug Transporter Interactions

A pharmacokinetic drug interaction study evaluated the effect of R. acetosa extract on the absorption of fexofenadine (an antihistamine that is a substrate of both P-glycoprotein [P-gp] and organic anion transporting polypeptides [OATPs]). The results clarified the inhibitory effect of emodin on P-gp through in vitro and in vivo study. In addition, R. acetosa extract could affect drug absorption via intervention in OATP-mediated influx and aqueous solubility. These results indicate that the effects of herbal medicines such as plant extracts on drug absorption must be considered in terms of not only efflux through P-gp, but also OATP-mediated influx and aqueous solubility. The extract may cause drug interactions when co-administered with substrates of drug transporters and poorly water-soluble drugs, although further clinical studies are needed.

This finding is clinically significant because P-gp and OATP substrates include a broad range of pharmaceutical drugs, and co-administration of substantial amounts of R. acetosa preparations with such drugs may alter their systemic exposure.

8.4 Mineral Absorption Interference

Consumption of Rumex spp. seems to be safe, but they could contain high amounts of oxalic acid. Oxalate can cause serious problems (calcium oxalate stone formation in the kidneys, decrease in iron absorption) in the case of consuming them in large amounts. This has particular relevance for individuals on iron or calcium supplementation, in whom the sorrel oxalate may reduce the therapeutic effectiveness of those supplements.

8.5 Antiplatelet Considerations

The extract exhibits anti-platelet activity via modulating MAPK, PI3K/Akt pathways and integrin αIIbβ3 signaling. Although this has not been evaluated in human clinical anticoagulation studies, the demonstrated in vitro and ex vivo antiplatelet mechanisms suggest a theoretical interaction with anticoagulant or antiplatelet medications; however, this has not been documented clinically at this time.

8.6 Overall Safety Characterization

A good safety and tolerability of Sinupret extract (containing R. acetosa as one of five components) was assured in all patients in the 929-patient randomised trial of chronic rhinosinusitis. Rumex acetosa should be taken with great care because of its high oxalate content. At food-level consumption, the plant is generally considered safe; the primary risks arise from consumption of large quantities of raw leaves or highly concentrated extracts, particularly in susceptible individuals.

References

• Wild vegetable Rumex acetosa Linn.: Its ethnobotany, pharmacology and phytochemistry – A review (ScienceDirect / South African Journal of Botany, 2019)
• The genus Rumex (Polygonaceae): an ethnobotanical, phytochemical and pharmacological review (PMC, 2022)
• Rumex Species: Phytochemistry, Pharmacology and Nutritional Potential for Food and Health Applications (PMC / Food Science & Nutrition, 2025)
• Antimutagenicity and cytotoxicity of the constituents from the aerial parts of Rumex acetosa (PubMed, 2005)
• Proanthocyanidins and a phloroglucinol derivative from Rumex acetosa L. (ScienceDirect / Fitoterapia, 2009)
• Herbal drug BNO 1016 is safe and effective in the treatment of acute viral rhinosinusitis (PMC / Acta Otolaryngologica, 2015)
• Assessment of efficacy and safety of the herbal medicinal product BNO 1016 in chronic rhinosinusitis (PubMed, 2017)
• Efficacy and effectiveness of BNO 1016 in the management of acute rhinosinusitis in the context of antibiotic stewardship (Postgraduate Medicine, 2023)
• Oligomeric proanthocyanidins from Rumex acetosa L. inhibit the attachment of herpes simplex virus type-1 (ScienceDirect / Antiviral Research, 2011)
• Oligomeric proanthocyanidins from Rumex acetosa L. inhibit the attachment of herpes simplex virus type-1 (PubMed)
• 3-O-Galloylated Procyanidins from Rumex acetosa L. Inhibit the Attachment of Influenza A Virus (PMC / PLoS ONE, 2014)
• Rumex acetosa modulates platelet function and inhibits thrombus formation in rats (BMC Complementary Medicine and Therapies, 2020)
• Effect of Rumex Acetosa Extract, a Herbal Drug, on the Absorption of Fexofenadine (PMC, 2020)
• Sorrel (Rumex acetosa L.): Not Only a Weed but a Promising Vegetable and Medicinal Plant (The Botanical Review, 2020)
• The Genus Rumex: Review of traditional uses, phytochemistry and pharmacology (ScienceDirect / Journal of Ethnopharmacology, 2015)
• Vasas et al. (2015) — The Genus Rumex: Review of traditional uses, phytochemistry, and pharmacology (full text PDF)
• Oligomeric proanthocyanidins from Rumex acetosa L. inhibit the attachment of herpes simplex virus type-1 (ResearchGate abstract)