There have been a few cases of persistent bleeding after surgery caused by herbal self-medication. Usually the patient forgets to tell the doctor that he or she is taking a supplement such as St. John's wort, ginseng, or ginkgo biloba.

Gingko biloba has an anticoagulant property much like aspirin. This means it prevents the blood from forming clots. That's important for patients at risk for heart attack or stroke, but it's a risk factor for anyone who's just had surgery or who has a bleeding disorder.

he most recent report of gingko biloba causing oozing from a wound after surgery comes from Wales. A 77-year old woman had a hip replacement without problems. Afterwards, the wound site drained blood and a clear fluid for three weeks. When it was finally discovered she was taking gingko biloba and she stopped taking it, the problem cleared up within 10 days.