Drug & supplement interaction

Cod Liver Oil + 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

Cod Liver Oil has a moderate interaction with Diclofenac Potassium. Theoretically, cod liver oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.

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

Cod Liver Oil and Diclofenac Potassium

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

Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

Why this applies to Diclofenac Potassium

Diclofenac Potassium falls under ANTICOAGULANT/ANTIPLATELET DRUGS — the group Cod Liver Oil interacts with.

Theoretically, cod liver oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
High doses of cod liver oil, 20-40 mL daily, have been associated with prolonged bleeding time and reduced platelet aggregation in healthy volunteers.
Severity Moderate Likelihood Possible Evidence B

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 thing to keep in mind with this combo. Diclofenac is an NSAID, and on its own it can already irritate the stomach lining and nudge up your bleeding risk a little, especially with longer use. Cod liver oil isn't a blood thinner in the classic sense, but the omega-3s (EPA and DHA) can make platelets a bit less sticky, so stacking the two could add up.

The good news is this is mostly theoretical, and the bleeding effect from cod liver oil showed up at high doses, around 20 to 40 mL a day. Normal food or modest supplement amounts are unlikely to cause trouble. Still, watch for things like easy bruising, dark stools, or stomach upset, and check with your pharmacist or doctor before combining them regularly.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Brox JH, Killie JE, Gunnes S, Nordoy A. The effect of cod liver oil and corn oil on platelets and vessel wall in man. Thromb Haemost 1981;46:604-11. DOI
  2. Sanders TA, Vickers M, Haines AP. Effect on blood lipids and haemostasis of a supplement of cod-liver oil, rich in eicosapentainoic and docosahexaenoic acids, in healthy young men. Clin Sci (Colch) 1981;61:317-24.
  3. Brox JH, Killie JE, Osterud B, et al. Effects of cod liver oil on platelets and coagulation in familial hypercholesterolemia (type IIa). Acta Med Scand 1983;213:137-44.. PubMed
  4. Lorenz R, Spengler U, Fischer S, Duhm J, Weber PC. Platelet function, thromboxane formation and blood pressure control during supplementation of the Western diet with cod liver oil. Circulation 1983;67(3):504-11. PubMed
  5. Ahmed AA, Holub BJ. Alteration and recovery of bleeding times, platelet aggregation and fatty acid composition of individual phospholipids in platelets of human subjects receiving a supplement of cod-liver oil. Lipids 1984;19(8):617-24. 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

Cod Liver Oil Also Interacts With Other Medications

Cod Liver Oil has 374 moderate 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 374 No known interaction 2,456 (incl. Diclofenac Potassium)
Taking anything else?

Check Another of Your Medications Against Cod Liver Oil

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

From our Q&A

Questions About Cod Liver Oil 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 Cod Liver Oil 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 Cod Liver Oil 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 Cod Liver Oil as Part of a Dietary Supplement Product? Check It for Interactions

We hold 17 real supplement products containing Cod Liver Oil, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Cod Liver Oil. Your product may carry other ingredients that interact with Diclofenac Potassium too, on top of Cod Liver Oil — 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 Cod Liver Oil 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 Cod Liver Oil
Steady interest

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

29 days ago today
Medication Diclofenac Potassium
Top half

#1,142 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 Cod Liver Oil

What is Cod Liver Oil?

Cod Liver Oil
  • Source of omega-3 fatty acids
  • Vitamin A and D supplementation
  • Heart health
  • Joint and bone health
  • Reducing inflammation

Cod liver oil supplies omega-3 fatty acids (EPA and DHA) along with vitamins A and D, and is popular for heart, joint, and general health support. Evidence is strongest for its nutrient content, but proof of specific disease benefits is mixed. Because it contains vitamin A, taking too much can be harmful, so check with your pharmacist or doctor before using it.

Read the full Cod Liver Oil 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 & Cod Liver Oil

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

0Major
374Moderate
0Minor
2,455No known interaction
374 Moderate 2,455 No interaction
Moderate

374 interactions

Showing 60 of 374 moderate interactions — see all 374 on the Cod Liver Oil page.

No interaction 2,455 drugs checked — show the list

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

Showing the 60 most looked-up of 2,455 medications checked with no known interaction — see the full Cod Liver Oil list.

See the full Cod Liver Oil 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
Cod Liver Oil 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 Cod Liver Oil and Diclofenac Potassium Together: Common Questions

Can you take Cod Liver Oil 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 Cod Liver Oil 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 Cod Liver Oil?

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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.