It has been around as a medicinal herb for approximately two thousand years. Two recent studies however have indicated that there may be negative interactions between St. John's Wort and a drug used in transplants, and also interference with a drug used in AIDS cocktails. In the far distant past, it appears to have been used as a topical salve or balm for burns and on wounds. During the Renaissance, the writings of Paracel suggested its use in a variety of conditions including psychological maladies, but not specifically as an antidepressant. The first specific reference to use of St. John's Wort as a treatment for depression occurred about 350 years ago when a Chemist, Angelo Sala, pointed out its use in treating melancholia.
Tea is a folk remedy for bladder ailments, depression, dysentery, diarrhea, and worms.
Experimentally it may be used as a sedative, anti-inflammatory, or antibacterial agent. It contains the biological active compounds choline, pectin, rutin, sitosterol, hypericin, and pseudohypericin. It goes on to warn that if applied externally, it may cause skin burns when exposed to sun. Recently, phytobiologists and chemists as well as psychopharmacologists who have studied St. John's Wort report it is effective in mild to moderate depression and in dysthymia as well as seasonal affective disorders. Another component of St. John's Wort is hyperforin, which has many neurochemical properties and may play a role in the antidepressant activity.