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    Herbal supplements and heart medicines may not mix

    Many herbal supplements can interact with prescription drugs. Some of these interactions can be life-threatening.
    By Mayo Clinic Staff
    April 01, 2026

    Herbal supplements are natural, so they must be safe, right? No, that's not true all the time.

    Herbal supplements can strongly affect the body. Some don't work well with prescription medicines. This is called a medicine interaction. Herbal supplements can interact with medicines used to treat heart and blood vessel conditions, such as high blood pressure and heart failure. Some medicine interactions can be risky.

    Herbal supplements and prescription medicines

    About half of adults in the United States say they have used one or more supplements in the past 30 days. Many older adults use them. But many people who take herbal supplements do not tell their healthcare professionals. And many people who use supplements also take medicines ordered for them by their healthcare professionals, called prescription medicines.

    Many herbal supplements may interact with heart disease medicines. For example, many herbal supplements that people use interact with the blood thinner warfarin (Jantoven).

    That's why you need to talk with your healthcare professional before you take herbal supplements if you also take prescription medicines. Your healthcare professional and pharmacist can help you stay away from unsafe interactions.

    Herbal supplements and drug interactions

    Many common herbal supplements interact with common heart medicines. If you take prescription medicines, be sure to talk to your healthcare professional before you take any herbal supplements. This list covers only some herbal supplements that have interactions.

    Coenzyme Q-10

    If you take coenzyme Q-10, it can lower:

    • How well warfarin works.
    • Your blood pressure, if you also take a drug to treat high blood pressure.

    Danshen

    Danshen can interact strongly with some heart medicines, such as:

    • Blood thinners. Danshen may raise your risk of bleeding. This can happen if you also take warfarin or other blood thinners, such as clopidogrel (Plavix) or aspirin, with danshen.
    • Blood pressure medicine. Danshen may make your blood pressure too low if you take danshen and a drug used to lower blood pressure. An example of a blood pressure drug is the calcium channel blocker diltiazem (Cardizem).
    • Digoxin (Lanoxin). If you take danshen and digoxin, it may add to the effects of digoxin and raise the risk of irregular heartbeat, also called arrhythmia. Digoxin is used to treat many heart conditions.

    Evening primrose

    Evening primrose may raise your risk of bleeding if you also take a blood thinner, such as:

    • Aspirin.
    • Clopidogrel.
    • Warfarin.

    Garlic

    Garlic may raise your risk of bleeding if you also take a blood thinner, such as:

    • Aspirin.
    • Clopidogrel.
    • Warfarin.

    Ginkgo biloba

    Ginkgo biloba may raise your risk of bleeding if you also take a blood thinner, such as:

    • Aspirin.
    • Clopidogrel.
    • Warfarin.

    Ginseng

    If you take ginseng with warfarin, it may lessen how well warfarin works.

    Hawthorn

    Hawthorn might interact with:

    • Beta blockers, such as atenolol (Tenormin), nadolol or propranolol (Inderal LA, Innopran XL).
    • Calcium channel blockers, such as diltiazem, nifedipine (Procardia) and verapamil (Verelan).
    • Nitrates, such as nitroglycerin (Nitrostat, Nitro-Dur, others) and isosorbide (Isordil).
    • Digoxin.

    Licorice

    The herb licorice may change how warfarin works and may raise bleeding risk. Licorice also can lower potassium levels, which can raise the risk of serious side effects from digoxin. Most licorice candies and products in the U.S. don't have any of the licorice herb in them.

    Saw palmetto

    Saw palmetto might make your risk of bleeding higher if you also take a blood thinner, such as:

    • Aspirin.
    • Clopidogrel.
    • Warfarin.

    St. John's wort

    It's not suggested to take St. John's wort if you take blood thinners. It also may keep some medicines from working as well as they should, such as:

    • Calcium channel blockers.
    • Digoxin.
    • Warfarin.
    • Statins, such as atorvastatin (Lipitor), lovastatin and rosuvastatin (Crestor).
    • Antirejection medicine, also called immunosuppressant medicine, such as cyclosporine (Gengraf, Neoral, Sandimmune).

    Be safe with herbal supplements

    If your healthcare professional tells you it's OK to use an herbal supplement along with medicine, be careful to follow directions about how much medicine to take. Watch for any signs that you may be having a drug interaction, such as:

    • Fast heartbeat.
    • Blood pressure changes.
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