Drug & supplement interaction

Rhubarb + Verapamil

Verapamil brand names: Isoptin SR, Verelan, Isoptin, Calan SR, Verelan SR, and others.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Rhubarb has a moderate interaction with Verapamil. Theoretically, concomitant use of rhubarb with potentially hepatotoxic drugs might increase the risk of developing liver damage.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Rhubarb and Verapamil

Here is the interaction we found between these two, with the evidence behind it.

Moderate

HEPATOTOXIC DRUGS

Why this applies to Verapamil

Verapamil falls under HEPATOTOXIC DRUGS — the group Rhubarb interacts with.

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.
Severity Moderate Likelihood Possible Evidence D

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.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the deal with rhubarb root and your verapamil. This isn't about rhubarb changing how verapamil works in your heart or blood vessels. Instead, the concern is about the liver. Verapamil is one of many medicines that can, in some people, put a little stress on the liver. Rhubarb root (the concentrated supplement, not the pie filling) contains compounds called anthraquinones that have been loosely tied to liver injury in a handful of reports.

The thinking is that stacking two things that may bother the liver could, in theory, add up. I want to be honest though: this is theoretical, based mostly on animal data and unclear case reports. Eating rhubarb stalks as food is very unlikely to matter. If you take a daily rhubarb supplement, mention it to your pharmacist or doctor so they can keep an eye on things.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Byeon JH, Kil JH, Ahn YC, Son CG. Systematic review of published data on herb induced liver injury. J Ethnopharmacol 2019;233:190-6. PubMed
  2. Zhao D, Feng SX, Zhang HJ, et al. Pharmacokinetics, tissue distribution and excretion of five rhubarb anthraquinones in rats after oral administration of effective fraction of anthraquinones from rheum officinale. Xenobiotica. 2021;51(8):916-925. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction 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.
  • PossibleInteraction 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.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Rhubarb Also Interacts With Other Medications

Rhubarb has 657 moderate known drug interactions in our database — the Verapamil one above is one of them. If you take anything else, check it against the full list below.

Moderate 657 No known interaction 2,173 (incl. Verapamil)
Taking anything else?

Check Another of Your Medications Against Rhubarb

Covers the 2,830 medications we’ve checked against Rhubarb. Pick one to open its full report.

From our Q&A

Questions About Rhubarb or Verapamil

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Rhubarb or Verapamil, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Verapamil

This page covers Rhubarb only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Verapamil page lists 295 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Beer (major) and Coleus (major).

By severity: 10 major · 245 moderate · 40 minor.

From our pharmacist’s overview on the Verapamil page

“This is one of the longer interaction lists we publish, and with verapamil (Calan, Verelan) it warrants genuine care, starting with the ten major-rated entries. Verapamil lowers blood pressure and slows the heart, so most of the 295 ingredients on file either push that effect further than intended or change how much of the drug reaches…”

Reviewed by 2 · Jul 18, 2026

Open the Verapamil interaction page

One more smart check

Taking Rhubarb as Part of a Dietary Supplement Product? Check It for Interactions

We hold 133 real supplement products containing Rhubarb, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Rhubarb. Your product may carry other ingredients that interact with Verapamil too, on top of Rhubarb — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Rhubarb and Verapamil Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Rhubarb
Top 25%

#234 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Verapamil
Top half

#804 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Rhubarb

What is Rhubarb?

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

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.

Read the full Rhubarb monograph & all interactions
Medication

About Verapamil

What Is Verapamil Used For?

Brand names: Isoptin SR, Verelan, Isoptin, Calan SR, Verelan SR, Calan, Covera HS, Verap, Veramil

Verapamil tablets and film-coated tablets are used to treat angina — including vasospastic (Prinzmetal's) angina, unstable angina, and chronic stable angina — as well as certain abnormal heart rhythms (arrhythmias) and high blood pressure (essential hypertension). For arrhythmias, regular-release tablets are used alongside digoxin to control heart rate in atrial flutter or atrial fibrillation, and to help prevent episodes of paroxysmal supraventricular tachycardia (SVT), a type of rapid heartbeat.

Extended-release and sustained-release oral forms (tablets and capsules) are indicated specifically for high blood pressure. Verapamil hydrochloride injection is used in hospital settings for rapid conversion of SVT to normal rhythm and for temporary control of fast heart rates in atrial flutter or atrial fibrillation.

See full Verapamil drug information
Keep checking

Other Drugs & Rhubarb

Browse every other medication we’ve checked against Rhubarb — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
657Moderate
0Minor
2,172No known interaction
657 Moderate 2,172 No interaction
Moderate

657 interactions

Showing 60 of 657 moderate interactions — see all 657 on the Rhubarb page.

No interaction 2,172 drugs checked — show the list

We also checked Rhubarb against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,172 medications checked with no known interaction — see the full Rhubarb list.

See the full Rhubarb interactions page
See every supplement checked against Verapamil, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Rhubarb monograph › Uses, safety, and every drug interaction in one place Verapamil supplement interactions › Every supplement checked against Verapamil, ranked by severity Verapamil drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Rhubarb and Verapamil Together: Common Questions

Can you take Rhubarb with Verapamil?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Rhubarb and Verapamil interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Verapamil and Rhubarb?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.