Drug & supplement interaction

Black Cohosh + Diclofenac Potassium

Diclofenac Potassium brand names: Voltaren Rapide, Cataflam, Cataflam IR, Voltarol Rapid, Cambia.

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

Black Cohosh has a moderate interaction with Diclofenac Potassium. Theoretically, taking black cohosh with hepatotoxic drugs may increase the risk of liver damage.

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

Black Cohosh and Diclofenac Potassium

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

Moderate

HEPATOTOXIC DRUGS

Why this applies to Diclofenac Potassium

Diclofenac Potassium falls under HEPATOTOXIC DRUGS — the group Black Cohosh interacts with.

Theoretically, taking black cohosh with hepatotoxic drugs may increase the risk of liver damage.
There is concern that black cohosh might be linked to cases of liver failure and autoimmune hepatitis.
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 simple version: both black cohosh and diclofenac can, on rare occasions, be hard on the liver. Diclofenac is a common anti-inflammatory for pain and arthritis, and it's already one of the NSAIDs we watch a little more closely for liver irritation. Black cohosh has its own scattered reports of liver trouble. The worry is that stacking two things that can stress the liver might raise the odds of a problem.

I want to be honest about the evidence though. This is mostly theoretical and based on a handful of anecdotal reports, not solid studies, so for most people taking either short-term it's a low-level concern. Still, watch for warning signs like yellowing skin or eyes, dark urine, belly pain, unusual tiredness, or nausea. Before combining them, check with your pharmacist or doctor, especially if you have any liver issues.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Whiting PW, Clouston A, Kerlin P. Black cohosh and other herbal remedies associated with acute hepatitis. Med J Aust 2002;177:440-3. PubMed
  2. Lontos S, Jones RM, Angus PW, Gow PJ. Acute liver failure associated with the use of herbal preparations containing black cohosh. Med J Aust 2003;179:390-1.. DOI
  3. Cohen SM, O'Connor AM, Hart J, et al. Autoimmune hepatitis associated with the use of black cohosh: a case study. Menopause 2004;11:575-7. PubMed
  4. Vitetta L, Thomsen M, Sali A. Black cohosh and other herbal remedies associated with acute hepatitis. Med J Aust 2003;178:411-2.. PubMed
  5. Cohen B, Schardt D. Center for Science in the Public Interest. Letter to Food and Drug Administration. Commissioner Mark McClellan, MD, PhD. March 4, 2004.
  6. Levitsky J, Alli TA, Wisecarver J, Sorrell MF. Fulminant liver failure associated with the use of black cohosh. Dig Dis Sci 2005;50:538-9. PubMed
  7. MHRA. Black cohosh (Cimicifuga racemosa) - risk of liver problems. Herbal Safety News July 2006. Available at: http://www.mhra.gov.uk/home/idcplg?IdcService=SS_GET_PAGE&useSecondary= true&ssDocName=CON2024131&ssTargetNodeId=663.
  8. Lynch CR, Folkers ME, Hutson WR. Fulminant hepatic failure associated with the use of black cohosh: a case report. Liver Transpl 2006;12:989-92. PubMed
  9. Brar HS, Marathi R. Case of cholestatic drug-induced liver injury (DILI) associated with black cohosh. BMJ Case Rep 2021;14(5):e240408. 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

Black Cohosh Also Interacts With Other Medications

Black Cohosh has 635 moderate, 16 minor known drug interactions in our database — the Diclofenac Potassium one above is one of them. If you take anything else, check it against the full list below.

Moderate 635 Minor 16 No known interaction 2,179 (incl. Diclofenac Potassium)
Taking anything else?

Check Another of Your Medications Against Black Cohosh

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

From our Q&A

Questions About Black Cohosh or Diclofenac Potassium

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

This page covers Black Cohosh only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Diclofenac Potassium page lists 306 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Beer (major), Danshen (major) and Piracetam (major).

Open the Diclofenac Potassium interaction page

One more smart check

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

We hold 1,472 real supplement products containing Black Cohosh, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Black Cohosh. Your product may carry other ingredients that interact with Diclofenac Potassium too, on top of Black Cohosh — 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 Black Cohosh and Diclofenac Potassium 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 Black Cohosh
Top 25%

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

29 days ago today
Medication Diclofenac Potassium
Top half

#929 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 Black Cohosh

What is Black Cohosh?

Black Cohosh
  • Hot flashes and night sweats
  • Other menopause symptoms
  • Mood changes during menopause
  • Premenstrual syndrome (PMS)
  • Menstrual cramps

Black cohosh is a North American plant most often used to ease menopause symptoms like hot flashes, but the research is mixed and far from settled. It is generally well tolerated for short-term use, though rare reports of liver problems mean you should talk with your pharmacist or doctor before trying it, especially if you have liver disease.

Read the full Black Cohosh monograph & all interactions
Medication

About Diclofenac

What Is Diclofenac Used For?

Brand names: Voltaren Rapide, Cataflam, Cataflam IR, Voltarol Rapid, Cambia

Diclofenac sodium topical gel is used to treat actinic keratoses (AK) — rough, scaly skin patches that form after years of sun exposure. These patches are considered precancerous, meaning they can develop into skin cancer if left untreated.

This is a topical gel, meaning it is applied directly to the skin over the affected area rather than taken by mouth. It belongs to the NSAID (nonsteroidal anti-inflammatory drug) family.

See full Diclofenac drug information
Keep checking

Other Drugs & Black Cohosh

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

0Major
635Moderate
16Minor
2,178No known interaction
635 Moderate 16 Minor 2,178 No interaction
Moderate

635 interactions

Showing 60 of 635 moderate interactions — see all 635 on the Black Cohosh page.

Minor

16 interactions

No interaction 2,178 drugs checked — show the list

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

Showing the 60 most looked-up of 2,178 medications checked with no known interaction — see the full Black Cohosh list.

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

Can you take Black Cohosh with Diclofenac Potassium?
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 Black Cohosh and Diclofenac Potassium 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 Diclofenac Potassium and Black Cohosh?

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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.