St. John's wort, botanically known as Hypericum perforatum is an aromatic, perennial plant that grows on dry, rough soil throughout much of the world's temperate regions. The use of St. John's wort as an herbal remedy for the treatment of various external and internal ailments has been known since ancient times. Since then, it has remained a popular treatment for depression, anxiety, cuts and burns. Recent research suggests the effectiveness of this plant in treating other diseases, including cancer, bacterial and viral diseases and as a neuroprotective agent and antioxidant. Furthermore, a dozen biologically active compounds have been isolated in St. John's wort preparations, but two- hypericin (a naphthodianthrone) and hyperforin (a phloroglucinol) show the highest medical activity. St. John's wort preparations show few harmful effects if taken alone at the recommended dosages. However, numerous interactions with other drugs have been reported. Recent research shows that St. John's wort ingredients have the ability to induce intestinal or hepatic enzymes that either remove drugs from the body or metabolize them to inactive forms.