Drug & supplement interaction

Comfrey + Abiraterone

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

Comfrey has a moderate interaction with Abiraterone. Theoretically, comfrey might have additive adverse effects on the liver when used with hepatotoxic drugs.

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

Comfrey and Abiraterone

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

Moderate

HEPATOTOXIC DRUGS

Why this applies to Abiraterone

Abiraterone falls under HEPATOTOXIC DRUGS — the group Comfrey interacts with.

Theoretically, comfrey might have additive adverse effects on the liver when used with hepatotoxic drugs.
Due to its pyrrolizidine alkaloid constituents, comfrey can cause hepatotoxic effects, including ascites, cirrhosis, hepatic fibrosis, hepatomegaly, and sinusoidal obstruction syndrome.
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 with pairing comfrey and abiraterone (Zytiga). Abiraterone is already known to stress the liver, and your care team likely checks your liver enzymes with regular blood tests while you're on it. Comfrey contains compounds called pyrrolizidine alkaloids that can also harm the liver, especially when taken by mouth. Putting two liver stressors together could, in theory, add up to more damage.

To be honest, this is a theoretical worry based on how these substances behave, not on documented cases with this exact combination. Still, since abiraterone needs a healthy liver to stay safe, I'd keep comfrey off your skin and never swallow it while on this drug. Please run any supplement past your oncology team or pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Food and Drug Administration. FDA Advises Dietary Supplement Manufacturers to Remove Comfrey Products From the Market. July 6, 2001. Available at: http://www.cfsan.fda.gov/~dms/dspltr06.html.
  2. Stickel F, Seitz HK. The efficacy and safety of comfrey. Public Health Nutr 2000;3:501-8. 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

Comfrey Also Interacts With Other Medications

Comfrey has 437 moderate known drug interactions in our database — the Abiraterone one above is one of them. If you take anything else, check it against the full list below.

Moderate 437 No known interaction 2,393 (incl. Abiraterone)
Taking anything else?

Check Another of Your Medications Against Comfrey

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

From our Q&A

Questions About Comfrey or Abiraterone

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Comfrey or Abiraterone, 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 Abiraterone

This page covers Comfrey only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Abiraterone page lists 181 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Grapefruit (major), Siberian Cocklebur (major) and St. John's Wort (major).

By severity: 6 major · 137 moderate · 38 minor.

From our pharmacist’s overview on the Abiraterone page

“Six of the 181 supplement entries on file for abiraterone (Zytiga), a hormone therapy for advanced prostate cancer, are rated major, and those six deserve your attention first. Grapefruit and St.”

Reviewed by 2 · Jul 18, 2026

Open the Abiraterone interaction page

One more smart check

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

We hold 29 real supplement products containing Comfrey, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Comfrey. Your product may carry other ingredients that interact with Abiraterone too, on top of Comfrey — 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 Comfrey and Abiraterone 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 Comfrey
Steady interest

#1,142 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Abiraterone
Steady interest

#1,582 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 Comfrey

What is Comfrey?

Comfrey
  • Bruises and sprains
  • Muscle and joint pain
  • Minor wounds and skin irritation
  • Back pain
  • Inflammation

Comfrey is a traditional herb used mainly on the skin for bruises, sprains, and joint pain, and some topical products show modest benefit for these uses. However, comfrey contains compounds that can seriously damage the liver, so it should never be taken by mouth and should only be used on unbroken skin for short periods. Pregnant or breastfeeding people should avoid it entirely.

Read the full Comfrey monograph & all interactions
Medication

About Abiraterone

What Is Abiraterone Used For?

Abiraterone acetate tablets are used to treat two types of advanced prostate cancer: metastatic castration-resistant prostate cancer (CRPC — cancer that has spread and keeps growing despite low testosterone levels) and metastatic high-risk castration-sensitive prostate cancer (CSPC — cancer that has spread but still responds to hormone-lowering treatment). It is always taken together with a corticosteroid — most products pair with prednisone, while Yonsa is specifically indicated with methylprednisolone.

All products — including Abiraterone, Abiraterone Acetate, Abirtega, Yonsa, and Zytiga — are taken by mouth as a tablet. Yonsa is approved only for metastatic CRPC, while the other products (Abiraterone, Abiraterone Acetate, Abirtega, and Zytiga) are approved for both metastatic CRPC and metastatic high-risk CSPC.

See full Abiraterone drug information
Keep checking

Other Drugs & Comfrey

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

0Major
437Moderate
0Minor
2,392No known interaction
437 Moderate 2,392 No interaction
Moderate

437 interactions

Showing 60 of 437 moderate interactions — see all 437 on the Comfrey page.

No interaction 2,392 drugs checked — show the list

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

Showing the 60 most looked-up of 2,392 medications checked with no known interaction — see the full Comfrey list.

See the full Comfrey interactions page
See every supplement checked against Abiraterone, 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
Comfrey monograph › Uses, safety, and every drug interaction in one place Abiraterone supplement interactions › Every supplement checked against Abiraterone, ranked by severity Abiraterone 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 Comfrey and Abiraterone Together: Common Questions

Can you take Comfrey with Abiraterone?
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 Comfrey and Abiraterone 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 Abiraterone and Comfrey?

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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.