NutriStack
Diclofenac and Fish Oil, a caution.
High-dose fish oil may add mild antiplatelet effects to diclofenac's GI bleeding risk. Standard omega-3 doses usually do not cause major bleeding in trials, but higher EPA/DHA doses and other bleeding risks can change the balance. The combination is more relevant with regular diclofenac use, prior ulcers, or procedures.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
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At a glance
- Substances
- Diclofenac and Fish Oil
- Pair type
- Caution
- Evidence (highest tier)
- Moderate
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Moderate evidence
Caution
What is happening. High-dose fish oil may add mild antiplatelet effects to diclofenac's GI bleeding risk. Standard omega-3 doses usually do not cause major bleeding in trials, but higher EPA/DHA doses and other bleeding risks can change the balance. The combination is more relevant with regular diclofenac use, prior ulcers, or procedures.
Mechanism. EPA and DHA can reduce platelet aggregation through altered thromboxane signaling. Diclofenac can cause GI mucosal injury through COX inhibition, so platelet effects may worsen bleeding if erosions occur.
Recommendation. Use caution with high-dose fish oil if you take diclofenac regularly. Tell your surgical or dental team about fish oil, and watch for bruising, black stools, vomiting blood, or nosebleeds.
Sources (2)
- Javaid M, Kadhim K, Bawamia B, Cartlidge T, Farag M, Alkhalil M. Bleeding Risk in Patients Receiving Omega-3 Polyunsaturated Fatty Acids: A Systematic Review and Meta-Analysis of Randomized Clinical Trials. J Am Heart Assoc. 2024;13(10):e032390. PMID 38742535
- Castellsague J, Riera-Guardia N, Calingaert B, Varas-Lorenzo C, Fourrier-Reglat A, Nicotra F, et al. Individual NSAIDs and upper gastrointestinal complications: a systematic review and meta-analysis of observational studies (the SOS project). Drug Saf. 2012;35(12):1127-1146. PMID 23137151
Stack Score
How this pair moves the number.
Effect on the composite score
If both Diclofenac and Fish Oil are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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