Herb & supplement monograph

Rhubarb Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Rhubarb interacts with medications. The heart of this page is the interaction list — every drug Rhubarb is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Rhubarb is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Rhubarb Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Rhubarb drug interaction appears low for most people, especially with occasional or food-level use. None of the listed interactions are rated major, and every one is based on theoretical or animal evidence rather than well-documented human studies.

Interactions deserving the most attention

The combinations that deserve the most care involve medicines with a narrow safety margin. Heavy or frequent rhubarb use acts as a stimulant laxative and can deplete potassium and fluid, which could raise bleeding risk with warfarin and increase the chance of toxicity with digoxin. Animal research also suggests rhubarb might lower levels of the transplant drug cyclosporine, and rhubarb has been linked to some reports of liver injury, so caution is sensible alongside medicines that can stress the liver.

What the rest of the list means

The long list of interacting medications looks more alarming than it is. Most entries trace back to the same theoretical concern, that overusing rhubarb as a laxative could upset fluid and potassium balance, rather than to proven harm in people. Typical, moderate use of rhubarb has not been shown to cause meaningful problems with most of these medicines.

Check your medications against Rhubarb

Based on HelloPharmacist’s Rhubarb interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Rhubarb

660 medications have a known interaction with Rhubarb, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Rhubarb using our pharmacist-reviewed interaction data.

AI summaries are generated from our Rhubarb interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Rhubarb combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Rhubarb affects

Every type of medication (drug category) Rhubarb is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 8 drug categories Rhubarb interacts with

CorticosteroidsCyclosporine (neoral, Sandimmune)Digoxin (lanoxin)Diuretic DrugsHepatotoxic DrugsNephrotoxic DrugsStimulant LaxativesWarfarin (coumadin)

Corticosteroids

Theoretically, frequent and high doses of rhubarb might increase the risk of hypokalemia when taken with corticosteroids.
Rhubarb has stimulant laxative effects. Overuse of rhubarb might compound corticosteroid-induced potassium loss.

Likelihood Possible Evidence D

Cyclosporine (Neoral, Sandimmune)

Theoretically, taking rhubarb with cyclosporine might reduce cyclosporine levels.
Animal research shows that co-administration of rhubarb decoction 0.25 or 1 gram/kg with cyclosporine 2.5 mg/kg, decreases cyclosporine maximum plasma concentration and overall exposure levels when compared with taking cyclosporine alone. The authors theorize that rhubarb might reduce cyclosporine bioavailability by inducing of P-glycoprotein and/or cytochrome P450 3A4. However, since rhubarb was administered as a single oral dose and enzyme induction usually occurs after multiple doses, it is possible that cyclosporine absorption was actually reduced via rhubarb's stimulant laxative effects. Also, the composition of the rhubarb decoction was not described.

Likelihood Possible Evidence D

Digoxin (Lanoxin)

Theoretically, overuse of rhubarb might increase the risk of adverse effects when taken with digoxin.
Rhubarb has stimulant laxative effects. Overuse of rhubarb might cause potassium depletion, increasing the risk of digoxin toxicity.

Likelihood Possible Evidence D

Diuretic Drugs

Theoretically, frequent and high doses of rhubarb might increase the risk of hypokalemia.
Rhubarb has stimulant laxative effects. Overuse of rhubarb might cause potassium depletion and compound diuretic-induced potassium loss.

Likelihood Possible Evidence D

Hepatotoxic Drugs

Theoretically, concomitant use of rhubarb with potentially hepatotoxic drugs might increase the risk of developing liver damage.
Some animal research suggests that anthraquinones in rhubarb might have hepatotoxic effects. Also, rhubarb use has been linked to at least 24 cases of liver injury, although details on the dose of rhubarb and duration of use in these cases is unclear.

Likelihood Possible Evidence D

Nephrotoxic Drugs

Theoretically, long-term use of anthraquinones from rhubarb might increase the risk of nephrotoxicity when used with nephrotoxic drugs.
The anthraquinone constituents of rhubarb have been shown to induce nephrotoxicity in animal research. Additionally, in a case report, a 23-year old female presented with kidney failure after taking 6 tablets of a proprietary slimming agent (found to contain the anthraquinones emodin and aloe-emodin from rhubarb) daily for 6 weeks and then adding diclofenac 25 mg 4 times daily for 2 days. The authors postulate that the anthraquinone constituents of rhubarb contributed to the renal dysfunction, and the addition of diclofenac, a nephrotoxic drug, led to renal failure. Until more is known, advise patients to avoid taking rhubarb if they are taking other potentially nephrotoxic drugs.

Likelihood Possible Evidence D

Stimulant Laxatives

Theoretically, rhubarb might increase the risk for fluid and electrolyte loss when taken with other stimulant laxatives.
Rhubarb has stimulant laxative effects. Concomitant use with stimulant laxatives might compound fluid and electrolyte loss.

Likelihood Possible Evidence D

Warfarin (Coumadin)

Theoretically, excessive use of rhubarb might increase the risk of bleeding when taken with warfarin.
Rhubarb has stimulant laxative effects and can cause diarrhea. Diarrhea can increase the effects of warfarin, increase international normalized ratio (INR), and increase the risk of bleeding. Advise patients who take warfarin not to take excessive amounts of rhubarb.

Likelihood Possible Evidence D

Monograph

Rhubarb: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Rhubarb root has a long history of use as a laxative and in traditional Chinese medicine, and its edible stalks are a common food. Most medicinal claims are backed by limited or low-quality evidence, and the root can cause cramping and diarrhea. The leaves are toxic and should never be eaten, and rhubarb supplements are best avoided in pregnancy and breastfeeding.

Scientific name: Rheum officinale
Family: Polygonaceae
Part used: Root, rhizome, and edible stalk (leaves are toxic and not used)
Common forms: Dried root powder, capsules, tablets, tinctures, teas, and culinary stalks

People commonly use it for

Constipation
Digestive upset
Menopausal symptoms
Kidney and liver conditions (traditional)
Pancreatitis (hospital/traditional use)

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

The stalks are a safe food, but the root used as a laxative can cause cramping and should not be used long-term.

PregnancyPossibly Unsafe

When used in medicinal amounts, rhubarb root is a stimulant laxative; avoid using.

Read the full pregnancy detail

BreastfeedingPossibly Unsafe

When used in medicinal amounts, rhubarb root is a stimulant laxative; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

Rhubarb is a leafy plant in the buckwheat family (Polygonaceae). Several species are used, including Rheum officinale and Rheum palmatum, often called Chinese rhubarb or Da Huang. It grows in parts of Asia, especially China and the Himalayas, and garden varieties are grown in cooler climates around the world.

The thick red or green stalks are a familiar food used in pies, jams, and sauces. In traditional medicine, however, it is the root and rhizome that are dried and used. These have been part of Chinese medicine for centuries, mainly as a laxative and for digestive complaints.

Importantly, the leaves are toxic because they contain high levels of oxalic acid and related compounds. Only the stalks and the medicinal root are used; the leaves should never be eaten.

How it works

Rhubarb root contains compounds called anthraquinones (such as emodin, aloe-emodin, and rhein). These stimulate the lining of the large intestine, which speeds up bowel movements and produces the laxative effect.

The root also contains tannins, which have an astringent, mildly binding effect. This is one reason rhubarb is sometimes described as both a laxative in larger amounts and an anti-diarrheal in smaller amounts.

Laboratory and animal studies suggest some rhubarb compounds may have anti-inflammatory or antioxidant activity. These findings are early and do not prove the same effects happen in people taking rhubarb.

Effectiveness

Does Rhubarb work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 18 uses evaluated

2 Possibly effective 16 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

Possibly Effective Menopausal symptoms