About 60 million Americans take dietary supplements or herbal remedies. If you're headed to the operating room, they could interact with numerous medications during surgery, so check your medicine cabinet and make a list of the supplements you are taking. Before going under the knife, give your doctor a list of all herbs and other supplements you’ve taken within the past month.

One common troublesome interaction is excessive bleeding during surgery, say experts at Brigham and Women's Hospital.

The following list includes 10 herbs that might interfere with surgery:

Garlic. May increase bleeding.
Goldenseal. May raise blood pressure or cause swelling, according to the Mayo Clinic.
Valerian. Could extend the effects of anesthesia.
Ginseng. May cause bleeding and raise high blood pressure.
Echinacea. May alter immune functioning and interfere with immunosuppressant drugs given after transplant surgery, says the Mayo Clinic.
Ginger. May cause bleeding.
Kava. May increase the effects of anesthesia.
St. John’s wort. May affect drugs used before and after surgery, either increasing or decreasing their effects.
Ginkgo. May cause bleeding during and immediately following surgery.
Aloe vera. May interfere with digestion and could also decrease the effectiveness of diuretics.

In addition, tell your doctor if you’re taking omega-3 fatty acids. More than three grams a day could cause internal bleeding. And also be sure to tell your doctor about any over-the-counter drugs you may take regularly. A baby aspirin each day may be heart healthy, but if you’re scheduled for surgery, your doc needs to know.

To be safe, stop taking all megadoses of vitamins, supplements, herbal medications at least two weeks before surgery.