St. John's Wort

Objective: The objective of this article is to review the current knowledge of the pharmacology, sites of action, and therapeutic effectiveness of St. John's Wort. Method: The method used was a review of the available literature, using keywords to search the medline database. Bibliographies of the papers, thus obtained, were searched for further documents not referenced by medline. We reviewed papers from this collection. Results: This review reveals that most of the available data on efficacy and safety of St. John's Wort involve its use in mild to moderate depression. Much, but not all of the prevailing opinion is positive. Nevertheless, the quality of therapeutic trials vary so greatly that definitive conclusions are not possible. Both the source and mode of St. John's Wort's therapeutic effect are unclear. We need further controlled studies of effectiveness, safety, and mode of action. In addition to its use in depression, there are reports suggesting possible therapeutic effects in other conditions such as certain malignancies and infections, but these are far too preliminary to permit any conclusions.