Hypericum perforatum L. is a plant, which has been traditionally used for various ethnopharmacological purposes, including treatment of mental disorders. Reported pharmacological activities of the plant extract on central nervous system have provided confirming evidence for several of the traditional uses of the plant. Preclinical studies on the central nervous system activities of the plant extracts have exhibited that, the extracts showed antidepressant, anxiolytic, sedative, nootropic, antischizophrenic, anticonvulsant, analgesic activities and was beneficial for the treatment of alcohol, nicotine and caffeine addiction in experimental animals. Following mentioned preclinical reports, several clinical data have confirmed the extracts or commercial preparations as effective as some standard antidepressants in mild to moderate depression. Plant extracts are also effective for the treatment of generalized anxiety disorders, somatoform disorders, sleep disorders, schizophrenia, obsessive-compulsive disorder and seasonal affective disorder. The central activity profile of the extracts is different form that of clinically used antidepressant drugs in terms of variety of the pharmacological effects. The extracts are suggested to provide additional advantage to avoid polypharmacy, considering that anxiety, sleep, and learning disorders accompany depression in most patients and complicated dementia cases are concurrent with depression especially in geriatric patients. Although results of studies are favorable in terms of pharmacological effects, patients should not take the Hypericum perforatum L. extracts without professional advice because of some possible adverse effects and drug-interactions of the plant.