This paper summarizes the antidepressant effects of certain Hypericum species on animal models. Although there are many drugs in clinical use for the management of human depression, most of the antidepressant drugs have undesirable side effects, some of which may limit the daily life of patients, and therefore, more specific agents with lesser side effects are necessary as a new therapeutic modality for the rational treatment of depression. In our laboratory, we observed antidepressant activity with the alcoholic extract of H. calycinum whose effects on the central nervous system of mice are almost equal to the extract prepared from St. John's wort, H. perforatum. Other species, H. hyssopifolium ssp. elongatum var. elongatum seems to have no antidepressant activity. From these data, it can be concluded that at least some of Hypericum species may have a potential use for the treatment of depression.
