Drug & supplement interaction

Rhubarb + Peginterferon alfa-2b

Peginterferon alfa-2b brand names: Peg-Intron, ViraferonPeg.

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

Rhubarb has a moderate interaction with Peginterferon alfa-2b. 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?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Rhubarb and Peginterferon alfa-2b

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

Moderate

HEPATOTOXIC DRUGS

Why this applies to Peginterferon alfa-2b

Peginterferon alfa-2b 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 concern in plain terms. Peginterferon alfa-2b is given for hepatitis C, and one of the things your care team watches closely during treatment is your liver. The drug itself can stress the liver and bump up liver enzymes on your blood tests. Rhubarb root (especially concentrated supplement doses, not the stalks in a pie) contains compounds called anthraquinones that, in some animal studies and a handful of human reports, have been linked to liver injury.

So the worry is simply doubling up on liver stress. To be clear, this is a theoretical interaction, not something proven in people on this drug. Still, since your liver is already the main target here, it's worth a quick chat with your doctor or pharmacist before using rhubarb supplements.

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 Peginterferon alfa-2b 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. Peginterferon alfa-2b)
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 Peginterferon alfa-2b

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 Peginterferon alfa-2b, 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 Peginterferon alfa-2b

This page covers Rhubarb only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Peginterferon alfa-2b page lists 38 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Beer (major), Siberian Cocklebur (major), Wine (major), Ashwagandha (moderate) and Black Cohosh (moderate).

By severity: 3 major · 35 moderate.

From our pharmacist’s overview on the Peginterferon alfa-2b page

“Someone taking peginterferon alfa-2b (Peg-Intron) is usually treating hepatitis C, so the liver is already the organ under strain, and all 38 supplement interactions on file for this drug pile additional liver stress on top of it. That earns genuine caution.”

Reviewed by 2 · Jul 18, 2026

Open the Peginterferon alfa-2b 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 Peginterferon alfa-2b 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 Peginterferon alfa-2b 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%

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

29 days ago today
Medication Peginterferon alfa-2b
Steady interest

#1,975 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 Peginterferon Alfa-2b (PEG-Intron)

What Is Peginterferon Alfa-2b (PEG-Intron) Used For?

Brand names: Peg-Intron, ViraferonPeg

  • Peginterferon alfa-2b is used alone or in combination with ribavirin (a medication) to treat chronic (long-term) hepatitis C infection (swelling of the liver caused by a virus) in people who show signs of liver damage and who have not been treated with interferon alpha (medication similar to peginterferon alfa-2b) in the past. Peginterferon alfa-2b is in a class of medications called interferons. Peginterferon alfa-2b is a combination of interferon and polyethylene glycol, which helps the interferon stay active in your body for a longer period of time. Peginterferon alpha-2b works by decreasing the amount of hepatitis C virus (HCV) in the body. Peginterferon alfa-2b may not cure hepatitis C or prevent you from developing complications of hepatitis C such as cirrhosis (scarring) of the liver, liver failure, or liver cancer. Peginterferon alfa-2b may not prevent the spread of hepatitis C to other people.

See full Peginterferon Alfa-2b (PEG-Intron) 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 Peginterferon alfa-2b, 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 Peginterferon alfa-2b supplement interactions › Every supplement checked against Peginterferon alfa-2b, ranked by severity Peginterferon Alfa-2b (PEG-Intron) 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 Peginterferon alfa-2b Together: Common Questions

Can you take Rhubarb with Peginterferon alfa-2b?
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 Peginterferon alfa-2b 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 Peginterferon alfa-2b and Rhubarb?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.