St. Johns (Janes Wort to a feminist) Wort has traditionally been used to treat melancholia, depression and exhaustion. Clinical trials have demonstrated that the herb is of benefit in mild to moderate depression only. Its anti-depressant effect may not become apparent for a week or two, and treatment may be long-term. However, if no significant improvement in depressive states is apparent after 4-6 weeks, its use should be discontinued. St. Johns Wort has been shown to improve sleep quality and cognitive function, and it is of value in the treatment of the emotional symptoms of menopause.