St. John's Wort (Hypericum perforatum): clinical effects on depression and other conditions.

St. John's Wort (Hypericum perforatum), a perennial flowering plant, has been used medicinally for thousands of years, and has most recently been identified as an effective treatment for mild to moderate depression. Clinical studies on the use of this plant for depression have utilized liquid tinctures and standardized solid extracts (0.3% hypericin--300 mg three times a day). Severe depression may also respond to this botanical, although it appears a larger dose is needed (600 mg solid extract three times a day). Hypericum has been favorably compared to numerous antidepressant drugs, the studies having revealed equivalent results and a much more favorable incidence of side effects. Studies have also demonstrated its efficacy in treating seasonal affective disorder. In vitro investigations of Hypericum show antiviral activity, although there is evidence these promising results might not occur in vivo. Traditional actions and uses include enhancement of wound healing, as well as anti-inflammatory and analgesic activity.