Safety and side effects

When taken as recommended, fish oil supplements are generally considered safe.

However, fish oil supplements can cause:

  • A fishy aftertaste
  • Bad breath
  • Indigestion
  • Nausea
  • Loose stools
  • Rash

Taking high doses of fish oil supplements might increase the risk of bleeding and possibly increase the risk of stroke.

It's unclear whether people with fish or shellfish allergies can safely take fish oil.

Interactions

Possible interactions include:

  • Anticoagulant and anti-platelet drugs, herbs and supplements. These types of drugs, herbs and supplements reduce blood clotting. It's possible that taking fish oil supplements with them might increase the risk of bleeding.
  • Blood pressure drugs, herbs and supplements. Taking fish oil supplements might slightly lower blood pressure. Taking these supplements with blood pressure drugs might increase the effects on blood pressure.
  • Contraceptive drugs. Some contraceptive drugs might interfere with the effect fish oil typically has on triglycerides.
  • Orlistat (Xenical, Alli). Taking fish oil with this weight-loss drug might decrease absorption of fish oil fatty acids. Consider taking the supplement and drug two hours apart.
  • Vitamin E. Taking fish oil can reduce vitamin E levels.
Oct. 24, 2017