Aims and method:
To assess and update the data on the use of St John's Wort as an antidepressant. A Medline search was conducted for the period January 1985 to December 1999. The search included other aspects of the usage of St John's Wort, such as side-effects, mechanism of action and drug interactions.
While two overviews and four clinical trials have recently been published, there is little data comparing St John's Wort against therapeutic doses of standard antidepressants.
St John's Wort is generally well tolerated, and an effective antidepressant. The current evidence indicates that it is less effective than standard antidepressants for severe depression. While some of the available data suggests equivalent efficacy as sub-therapeutic doses of tricyclic antidepressants in mild to moderate depression this requires further confirmation. One recently published paper suggests that St John's Wort has equivalent efficacy to fluoxetine in mild to moderate depression. The appropriate therapeutic dose needs clarification.