St. John`s Wort has been the most widely used medicine. Europeans and native people treating many ailments, including diarrhea. tuberculosis,bladder problems and worms. Tea is taken to treat all of these problems and also it is a sedative and well known as an antidepressant Hypericin inhibits the enzyme monoamine oxidase, thereby increasing the activity of nerve-impulse transmitters in the brain that are critical to mood and emotional stability. Oil extracts have been given internally to treat chronic stomach inflammation and stomach ulcers. They have also been applied externally to heal cuts, scrapes, and mild burns, and to relieve sciatica, back spasm, neck cramps and associated stress headaches. Two antiviral agents in this plants hypericin and pseudohypericin are being studied for use in treatment of AIDS.