What about St. John's wort?
The extract from the herb St. John's wort (Hypericum perforatum) has been used for centuries in many folk and herbal remedies. Today in Europe, it is used extensively to treat mild to moderate depression. However, recent studies have found that St. John’s wort is no more effective than placebo in treating major or minor depression.
In 2000, the FDA issued a Public Health Advisory letter stating that the herb may interfere with certain medications used to treat heart disease, depression, seizures, certain cancers, and those used to prevent organ transplant rejection. The herb also may interfere with the effectiveness of oral contraceptives. Consult with your doctor before taking any herbal supplement.