What is Rhubarb Root (Persian Rewash)?

Rhubarb root — known in Persian tradition as Rewash or Rewand — is the thick underground root of medicinal rhubarb species, distinct from the garden rhubarb used in cooking. It has been prized in Persian, Chinese, and Ayurvedic medicine for millennia, and was one of the most expensive herbal imports into medieval Europe, traded along the Silk Road at prices rivaling saffron. Today it is used in both traditional and integrative medicine as a digestive aid, anti-inflammatory, and hormonal support herb.

How does Rhubarb Root (Persian Rewash) work?

Rhubarb root works through two complementary mechanisms depending on the dose. At lower doses, its tannins and polyphenols have an astringent, anti-inflammatory effect that can actually firm up loose stools and soothe gut irritation. At higher doses, its anthraquinone compounds stimulate the colon to move things along, making it one of nature's most effective laxatives. It also contains stilbene compounds — particularly rhapontigenin — that interact with estrogen receptors, which helps explain its benefit for menopausal symptoms like hot flashes.

What forms does Rhubarb Root (Persian Rewash) come in?

Dried root powder and decoctions are traditional and potent. Standardized extracts (often standardized to anthraquinone or stilbene content) offer more predictable dosing and are preferred for therapeutic use. Capsules and tablets are the most convenient modern forms. Tinctures are available but less common. For menopausal support, a specific extract called ERr 731 (from Rheum rhaponticum) has been studied in clinical trials.

Where it comes from:

Persian physicians including Ibn Sina (Avicenna) described Rewash extensively in the Canon of Medicine as a superior digestive tonic and liver cleanser, distinguishing it from inferior rhubarb varieties. Chinese medicine has used Da Huang for over 2,000 years as one of the foundational 'purging' herbs. During the 16th to 18th centuries, medicinal rhubarb root was so valuable in Europe that wars and trade policies were shaped around its supply — at times worth more by weight than opium.

What does Rhubarb Root (Persian Rewash) help with?

• Constipation and sluggish digestion: Rhubarb root is one of the most reliable herbal laxatives available. Its anthraquinone compounds gently stimulate the colon, encouraging movement and relieving backed-up digestion without the harshness of synthetic laxatives when used correctly. It works best for occasional constipation rather than daily ongoing use.
• Menopausal hot flashes and night sweats: A specific rhubarb root extract (ERr 731, from Rheum rhaponticum) has been studied in clinical trials for menopausal symptoms and shown meaningful reduction in hot flash frequency and intensity. Its stilbene compounds act as mild phytoestrogens, helping smooth out the hormonal fluctuations that trigger hot flashes without the risks associated with conventional hormone therapy.
• Liver health and detox support: Traditional Persian and Chinese medicine both classified rhubarb root as a primary liver herb, used to clear heat and stagnation from the liver. Modern research suggests its compounds — particularly emodin and rhein — help reduce liver inflammation and support bile flow, which is central to how the liver processes and eliminates toxins.
• Gut inflammation and leaky gut: Rhubarb root's tannins and polyphenols help calm inflammation along the digestive tract and may support the integrity of the gut lining. In Chinese integrative medicine, rhubarb-based formulas are used to manage inflammatory bowel conditions, and some clinical research supports reduced markers of gut inflammation.
• High cholesterol: Several studies, particularly from Chinese clinical research, suggest that rhubarb supplementation can modestly reduce total cholesterol and LDL levels. Its fiber-like polysaccharides and anthraquinones appear to reduce cholesterol absorption in the gut while supporting its excretion.
• Blood sugar management: Emodin and other rhubarb compounds have been shown in clinical research to improve insulin sensitivity and help lower fasting blood sugar, making rhubarb root a traditional and emerging modern adjunct for metabolic health support. Effects are modest and work best alongside dietary changes.
• Kidney health (chronic kidney disease support): Rhubarb root has been used extensively in Chinese integrative nephrology to slow the progression of chronic kidney disease. Its compounds appear to reduce nitrogen waste buildup and kidney inflammation, and several controlled trials have shown it can help preserve kidney function in early to moderate CKD stages.
• Diarrhea and gut irritation (low dose): This one surprises people — at low doses, rhubarb root actually does the opposite of its laxative effect. The tannins take charge at small amounts, tightening the gut lining and reducing loose, irritated bowel movements. Traditional herbalists have long used it bidirectionally depending on dose.
• Skin inflammation (topical use): Rhubarb root preparations have been applied topically in traditional medicine for skin redness, irritation, and slow-healing wounds. Its antimicrobial and anti-inflammatory compounds help calm irritated skin, and emodin in particular has been studied for its ability to inhibit certain skin pathogens.

What can Rhubarb Root (Persian Rewash) help prevent?

• Progressive kidney function decline in early chronic kidney disease (supported by controlled clinical trials)
• Recurrence of certain digestive complications post-surgery (studied in Chinese clinical settings)

Which foods are rich in Rhubarb Root (Persian Rewash)?

1. Garden rhubarb stalks (Rheum rhabarbarum): The closest food form — rhubarb stalks contain small amounts of anthraquinones, oxalic acid, and polyphenols found in the root, though in much lower therapeutic concentrations. The stalks are edible; the leaves are toxic.
2. Aloe vera juice: Contains aloe-emodin and other anthraquinones that overlap with rhubarb root's digestive and laxative compounds, supporting similar gut-motility pathways.
3. Cascara sagrada (as a tea): Another anthraquinone-rich botanical used as a digestive aid, sharing the same active compound class as rhubarb root for gut motility support.
4. Senna tea: Contains sennosides closely related to those in rhubarb root, producing comparable laxative and colon-stimulating effects.
5. Red grape and berries (for stilbene/resveratrol content): Grapes, blueberries, and mulberries contain resveratrol and related stilbenes that share biological overlap with rhubarb's rhapontigenin, supporting antioxidant and mild phytoestrogenic pathways.

Practical Tips:

Rhubarb root as a medicinal herb is not meaningfully obtained through diet alone — therapeutic doses require supplemental forms. To support rhubarb root's core benefits (liver health, gut motility, inflammation), emphasize a fiber-rich, plant-forward diet with plenty of leafy greens, legumes, fermented foods, and bitter vegetables like dandelion greens and artichoke, which support bile flow and gut health through overlapping mechanisms.

What are the side effects of Rhubarb Root (Persian Rewash)?

• Stomach cramping or griping (especially at higher laxative doses)
• Loose stools or diarrhea
• Electrolyte loss (potassium, sodium) with prolonged use
• Harmless orange or reddish discoloration of urine
• Nausea (less common)
• Bowel dependency with extended overuse
• Kidney stone risk with very prolonged use (oxalate content)
• Not safe during pregnancy (stimulates uterine contractions)
• Not recommended while breastfeeding

Good to know:

Rhubarb root is safe for most healthy adults when used short-term at appropriate doses. Long-term or high-dose use carries real risks including electrolyte loss, dependency of the bowel, and kidney stress from oxalate accumulation. It should not be used during pregnancy, by children, or by people with inflammatory bowel disease, kidney stones, or intestinal obstruction.

How much Rhubarb Root (Persian Rewash) should you take?

• Recommended daily: Laxative use: 1–2 g of dried root powder or standardized extract (20–30 mg anthraquinones) before bed. Menopausal support (ERr 731 extract): 4 mg standardized extract daily, as studied in trials. Digestive tonic/anti-inflammatory (low dose): 0.1–0.5 g daily. Always start at the lowest effective dose.
• Best time of day: For constipation: take at bedtime to allow overnight action. For menopausal or anti-inflammatory use: with your largest meal of the day.
• With or without food: Take with food or a full glass of water to reduce stomach irritation and support absorption. Do not take on an empty stomach at higher doses.
• Time to effect: Laxative effect: 6–12 hours. Menopausal symptom relief: 4–12 weeks of consistent use. Digestive and anti-inflammatory benefits: 4–8 weeks.
• How long to take it: Limit laxative-dose use to no more than 1–2 weeks at a time without a break. For menopausal and anti-inflammatory purposes, clinical studies have used it for up to 12 weeks continuously — longer use should be supervised by a healthcare provider. Cycle off for at least 2 weeks between rounds of use.