Medications · Supplements
Fish Oil (Omega-3) Before Surgery
Fish oil is one of the most popular supplements — and one most worth pausing before surgery, because omega-3 gently thins the blood.
The short answer
Why fish oil matters before surgery
Omega-3 fatty acids make blood platelets a little less sticky, which is part of why fish oil is taken for heart health — but during surgery that same effect can mean more bleeding and bruising. Stopping it a week or two ahead lets your normal clotting return before the operation.
When to stop
About 1–2 weeks before is the usual cautious window, and a little longer if you might have a spinal, epidural or nerve block, which need your clotting fully normal. Your team gives the final timing — and there's no need to do anything dramatic; just stop the capsules when advised.
Frequently asked questions
How long before surgery should I stop fish oil?
Usually about 1–2 weeks before. Omega-3 reduces how well platelets clump together, so stopping it in good time lets your clotting return to normal before the operation. Confirm the exact timing with your team.
Is fish oil really a problem for surgery?
It has a mild blood-thinning effect, which is why surgeons commonly ask you to stop it, especially before operations where bleeding or bruising matters (and before a spinal or epidural). It's a sensible precaution rather than a major danger — but do disclose it.
Can I eat fish before surgery?
Yes — eating fish as food is fine and isn't the same as taking concentrated fish-oil capsules. It's the high-dose supplement that's stopped. (Just follow your normal fasting rules on the day.)