Do supplements interact with drugs?

Yes. Dietary supplements can interact with prescription and over-the-counter medications. They may increase or decrease a drug’s effect or raise the risk of side effects.

Examples include: vitamin K and blood thinners (e.g. warfarin); St. John’s wort and many prescription drugs; calcium or iron and some antibiotics (reducing absorption); high-dose fish oil and blood thinners; and others. Herbs and high-dose vitamins or minerals are especially important to review. Always tell your doctor and pharmacist what supplements you take. If you are starting or stopping a supplement, ask whether it could interact with your medications. This is educational only; your healthcare team can give you personalized advice.