Resveratrol acts on many different tissues in the body. It is chemically related to estrogen. In some situations, high doses of resveratrol boost the activity of estrogen, in others they block estrogen. That makes resveratrol supplements iffy for women with cancer of the breast, ovary, uterus, or other estrogen-sensitive tissue, those trying to become pregnant, or those taking an oral contraceptive. Resveratrol makes platelets in the bloodstream less “sticky,” and so could increase the risk of bleeding in people who take warfarin (Coumadin), clopidogrel (Plavix), aspirin, ibuprofen, or other nonsteroidal anti-inflammatory drugs. harvard uni isotonix reservatrol faq Dietary Supplements: Safety, Efficacy and Quality. Katja Berginc,Samo Kreft anthocyanin and heparin : 長庚紀念醫院 消費者委員會: 藍莓精華可改善視力的聲稱