Rheum rhabarbarum (Rheum rhabarbarum): Benefits, Dosage, Safety & Evidence

Frequently asked questions

How does rhubarb root work as a laxative?

Rhubarb root contains anthraquinone compounds, primarily emodin and aloe-emodin, which stimulate peristalsis in the large intestine. These compounds increase fluid secretion into the intestinal lumen and activate the myenteric plexus, promoting bowel movements within 6-12 hours of ingestion. The tannins present also provide astringent effects that may help balance the laxative action. Evidence level: C.

Does rhubarb root interact with any medications?

Rhubarb root may interact with several medications due to its laxative effects and anthraquinone content. It can reduce absorption of oral medications by decreasing gut transit time and may potentiate potassium loss when combined with diuretics, corticosteroids, or cardiac glycosides like digoxin. Long-term use may cause electrolyte imbalances that affect heart medications. Patients taking prescription medications should consult a healthcare provider before use. Evidence level: C.

What is the recommended dosage of rhubarb root?

For laxative purposes, the typical adult dose of dried rhubarb root is 1-4 grams daily, taken as a decoction or in capsule form. For tonic or liver-supportive purposes, a lower dose of 0.5-1 gram is traditionally used. Rhubarb root should not be used continuously for more than 8-10 days without medical supervision, as dependence may develop. Evidence level: Traditional/C.

Is rhubarb root safe during pregnancy?

Rhubarb root is contraindicated during pregnancy and is considered unsafe. The anthraquinone compounds stimulate uterine contractions and may cause miscarriage or premature labor. Additionally, the strong laxative effects can cause significant fluid and electrolyte losses that may harm both mother and fetus. Pregnant women should avoid all medicinal rhubarb root preparations, though culinary rhubarb stalks contain minimal anthraquinones and are generally considered safe in normal food amounts. Evidence level: C.

What are the side effects of taking rhubarb root?

Common side effects of rhubarb root include abdominal cramping and diarrhea, particularly at higher doses. Long-term use can lead to electrolyte imbalances, especially potassium deficiency, and may cause melanosis coli, a benign pigmentation of the colon lining. Chronic use can result in laxative dependence, where the colon becomes unable to function without stimulation. People with inflammatory bowel disease or intestinal obstruction should avoid rhubarb root entirely. Evidence level: C.

PubMed-compiled information sheet

This sheet was compiled from PubMed (NIH) abstracts using AI assistance. Every factual claim is cited to a real PubMed article (see the source list). It has not yet been human-reviewed — confirm with a healthcare provider before use.

Compiled from 29 PubMed articles · model: gemma4:31b

Summary

Rheum rhabarbarum (garden rhubarb) is an edible and medicinal species used for centuries in traditional medicine, particularly in Asia and Europe [PMID:37421780, PMID:41744006].

Background

Rheum rhabarbarum is a perennial herb cultivated in various regions, including China [PMID:30708823]. It is recognized as generally recognized as safe (GRAS) as a food by the U.S. Food and Drug Administration [PMID:30000922].

Traditional uses

Traditional medicine recommends its use for over thirty complaints, including cardiovascular disorders (heartache, pericardium pains, epistaxis, and other hemorrhages), blood purification, and venous circulation disorders [PMID:37201663]. It has also been used to treat constipation, gout, chronic renal failure, and upper gastrointestinal bleeding [PMID:30000922, PMID:30708823]. Topical applications have been used for gingivitis and herpes infections [PMID:30000922].

Active compounds

The plant contains anthraquinones (including aloe-emodin, chrysophanol, emodin, and rhein), tannins, stilbenes (rhapontigenin and rhaponticin), flavonoids, polyphenols, anthocyanins, organic acids (citric, oxalic, and succinic), and vitamins [PMID:30000922, PMID:37421780, PMID:28426978, PMID:36810439].

Mechanism of action

Rhein inhibits hydrogen-peroxide-induced oxidative stress in intestinal epithelial cells via PI3K/Akt-mediated Nrf2/HO-1 pathways [PMID:30779558]. Aloe-emodin inhibits lipopolysaccharide-induced inflammatory responses in macrophages [PMID:24685589]. Extracts may promote incision healing by relieving inflammation and stimulating angiogenesis [PMID:27592494].

Clinical evidence

Evidence BAcute diverticulitis

A randomized trial of the Kampo formula daiobotanpito (containing rhubarb) combined with antibiotics showed no significant difference in treatment success rates compared to placebo, though it showed a significant reduction in inflammatory response [PMID:40595170]

Evidence DIncision healing

Extract of Rheum rhabarbarum was found to promote the healing of incisions by decreasing leukocytes and neutrophils and inhibiting bacterial growth [PMID:27592494]

Safety & adverse effects

Rhubarb (Da Huang) has been identified in reports of herbal-induced liver injury (hepatotoxicity) [PMID:26357619, PMID:25536637].

Pregnancy & lactation

Rhubarb should not be used during breastfeeding due to possible cathartic effects on the breastfed infant, although older studies suggested laxative doses did not pass into milk [PMID:30000922].

Evidence summary

Evidence is primarily based on in vitro studies, traditional use reports, and a few clinical trials; high-level systematic evidence for specific therapeutic claims is lacking.

PubMed sources

1.PMID: 30000922 (2006) — Rheum rhaponticum and Rheum rhabarbarum Extracts as Modulators of Endothelial Cell Inflammatory Response. · Nutrients
2.PMID: 37201663 (2023) — Effects of Rheum rhaponticum and Rheum rhabarbarum extracts on haemostatic activity of blood plasma components and endothelial cells in vitro. · Journal of ethnopharmacology
3.PMID: 37421780 (2023) — Anti-inflammatory and antioxidant actions of extracts from Rheum rhaponticum and Rheum rhabarbarum in human blood plasma and cells in vitro. · Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie
4.PMID: 24685589 (2014) — Aloe-emodin from rhubarb (Rheum rhabarbarum) inhibits lipopolysaccharide-induced inflammatory responses in RAW264.7 macrophages. · Journal of ethnopharmacology
5.PMID: 41744006 (2025) — Historical studies on the use of Rhubarb in Japan.

Rheum rhabarbarum

Sources & Citations

Calculate a safe dose of Rheum rhabarbarum