Drug & supplement interaction

Evening Primrose + Clopidogrel

Clopidogrel brand name: Plavix.

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

Clopidogrel falls into 2 drug categories that Evening Primrose can interact with; the most serious is rated moderate. Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Evening Primrose and Clopidogrel

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Evening Primrose interacts with whole categories of medication. Clopidogrel falls into 2 of those categories, so it can interact with Evening Primrose in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

1 of 2

Why this applies to Clopidogrel

Clopidogrel falls under ANTICOAGULANT/ANTIPLATELET DRUGS — the group Evening Primrose interacts with.

Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Evening primrose oil contains gamma linolenic acid (GLA). There is preliminary clinical evidence that GLA can reduce platelet aggregation and prolong bleeding time.
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 gist with Plavix (clopidogrel) and evening primrose oil. Clopidogrel already does one main job: it keeps your platelets from clumping together so you don't form dangerous clots. Evening primrose oil contains GLA, and there's some early lab and clinical hints that GLA can also make platelets a little less sticky and lengthen bleeding time. So the worry is that the two could nudge in the same direction and add up to a bit more bleeding risk.

This isn't a sure thing. The concern is mostly theoretical, based on how GLA behaves rather than strong proof. Still, if you take both, keep an eye out for things like easy bruising, nosebleeds, bleeding gums, or cuts that are slow to stop. Don't change anything on your own; just give your pharmacist or doctor a quick heads-up so they can weigh in.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Guivernau M, Meza N, Barja P, Roman O. Clinical and experimental study on the long-term effect of dietary gamma-linolenic acid on plasma lipids, platelet aggregation, thromboxane formation, and prostacyclin production. Prostaglandins Leukot Essent Fatty A PubMed
Minor

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

2 of 2

Clopidogrel also falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES.

Theoretically, evening primrose may increase the levels and clinical effects of CYP2C9 substrates.
In vitro research shows that linoleic acid, a constituent of evening primrose oil, inhibits CYP2C9.
Severity Minor 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 wrinkle with clopidogrel (Plavix): it's a prodrug. That means it does nothing until your liver enzymes flip it into its active, clot-fighting form. So an enzyme that gets a little blocked could actually leave you with less active drug, not more. That said, clopidogrel mainly depends on a different enzyme (CYP2C19) for that activation, so this particular CYP2C9 note doesn't line up neatly with how Plavix works.

On top of that, this concern is purely theoretical, based on a lab (test-tube) finding with one component of evening primrose oil. There's no solid human evidence it changes how Plavix performs. Since both can nudge bleeding risk, it's still worth a quick word with your pharmacist or doctor before adding the supplement, especially if you bruise easily or notice unusual bleeding.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Zou L, Harkey MR, and Henderson GL. Effects of herbal components on cDNA-expressed cytochrome P450 enzyme catalytic activity. Life Sci 8-16-2002;71(13):1579-1589. 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

Evening Primrose Also Interacts With Other Medications

Evening Primrose has 147 moderate, 85 minor known drug interactions in our database — the Clopidogrel one above is among them. If you take anything else, check it against the full list below.

Moderate 147 Minor 85 No known interaction 2,598 (incl. Clopidogrel)
Taking anything else?

Check Another of Your Medications Against Evening Primrose

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

From our Q&A

Questions About Evening Primrose or Clopidogrel

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

This page covers Evening Primrose only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Clopidogrel page lists 309 supplements it has a documented interaction with, worst first, each one explained.

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

By severity: 5 major · 258 moderate · 46 minor.

From our pharmacist’s overview on the Clopidogrel page

“Clopidogrel (Plavix) keeps platelets from sticking together after a stent, heart attack, or stroke, which makes this a list to take carefully. Of the 309 supplements and herbs on file, 202 carry blood-thinning or antiplatelet activity of their own and can stack bleeding risk on top of the drug's, while most of the rest change how the l…”

Reviewed by 2 · Jul 18, 2026

Open the Clopidogrel interaction page

One more smart check

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

We hold 98 real supplement products containing Evening Primrose, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Evening Primrose. Your product may carry other ingredients that interact with Clopidogrel too, on top of Evening Primrose — 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 Evening Primrose and Clopidogrel 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 Evening Primrose
Top half

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

29 days ago today
Medication Clopidogrel
Top 1%

#15 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 Evening Primrose

What is Evening Primrose?

Evening Primrose
  • Eczema and skin health
  • PMS symptoms
  • Breast pain (mastalgia)
  • Menopause symptoms
  • Inflammation
  • Diabetic nerve pain

Evening primrose oil is a seed oil rich in gamma-linolenic acid (GLA), an omega-6 fatty acid, that is popularly used for skin conditions, PMS, and breast pain. The evidence behind most of these uses is mixed or weak, and it is not proven to be a reliable treatment for any condition. It is generally well tolerated for short-term use, but talk to your pharmacist or doctor before starting it, especially if you are pregnant or have a bleeding disorder.

Read the full Evening Primrose monograph & all interactions
Medication

About Clopidogrel

What Is Clopidogrel Used For?

Brand name: Plavix

Clopidogrel tablets are used to reduce the risk of heart attack and stroke in people with acute coronary syndrome (ACS) — including unstable angina and non-ST-elevation or ST-elevation heart attacks — and in people with a history of recent heart attack, recent stroke, or established peripheral arterial disease. For ACS, it is typically given alongside aspirin.

It works by preventing platelets (blood cells that trigger clotting) from clumping together, which helps keep arteries open and lowers the chance of a dangerous clot forming.

See full Clopidogrel drug information
Keep checking

Other Drugs & Evening Primrose

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

0Major
147Moderate
85Minor
2,597No known interaction
147 Moderate 85 Minor 2,597 No interaction
Moderate

147 interactions

Showing 60 of 147 moderate interactions — see all 147 on the Evening Primrose page.

Minor

85 interactions

Showing 60 of 85 minor interactions — see all 85 on the Evening Primrose page.

No interaction 2,597 drugs checked — show the list

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

Showing the 60 most looked-up of 2,597 medications checked with no known interaction — see the full Evening Primrose list.

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

Can you take Evening Primrose with Clopidogrel?
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.
Why are there 2 interactions listed for Evening Primrose and Clopidogrel?
Clopidogrel belongs to more than one drug category, and Evening Primrose interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Evening Primrose and Clopidogrel 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 Clopidogrel and Evening Primrose?

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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.