St. John's Wort is native to Europe, West Asia, North Africa, Madeira and the Azores, and is naturalised in many parts of the world, notably North America and Australia. The native North Americans used several indigenous species of Hypericum as an abortifacient, antidiarrheal, dermatological aid, febrifuge, hemostat, snake bite remedy, and general strengthener.

It is the hypericin chemicals which have the pharmacological effects. Drying of the fresh plant in sunlight will destroy up to 80% of the hypericin. A commercial oil or tincture of Hypericum made only from the fresh plant, should be vivid, almost fluorescent red. If the preparation is pale red to pink, the hypericin content, and thus the quality of the product, is suspect. The oil is used to treat bruises, burns, wounds, back pain, varicose veins, hemorrhoids, sunburn, tumors, herpes and nerve pain. It can help heal damaged nerves when used internally and topically. The taste (and smell) of St. John's Wort is characteristically slightly sweet, bitter, and astringent. It's pharmacological actions are antidepressant, antiseptic, antiviral, aromatic, astringent, diuretic (weak) & anti-enuretic, pectoral, resolvent, nervine. Topically also as mild analgesic.

St. John's Wort is a valuable antidepressant and is characterised as calming, sedative, anti-inflammatory and astringent. It is used to treat menopausal problems, rheumatism, anxiety, depression, coughs & colds. As a practical folk-remedy, it has been used widely to heal wounds, and alleviate nervous disorders, bladder trouble, dysentery, diarrhea, even insanity. Other popular uses have included: as a decoction for gravel and ulcerations of the ureter; for ulcerations of the kidneys, febrifuge, vermifuge, jaundice and gout; as an infusion for chronic catarrhs of the lungs, bowels, or urinary passages; and as a warm lotion on injuries to the spinal cord, for lacerated or injured nerves, bed sores, and lock-jaw.


One German patent mentions that an ointment containing an extract of St. John's Wort flowers shortened healing time of burns and showed antiseptic activity. According to the report, first degree burns healed in 48 hours when treated with the ointment, while second and third degree burns healed without keloid (a type of scar tissue) formation three times faster than burns treated by conventional methods.

St. John's Wort is currently official in the pharmacopoeias of the Czech & Slovak Republics, Poland, Romania, and the Russian C.I.S.

St. John's Wort can cause sickness and even death in grazing animals (when large amounts are eaten), particularly cattle, sheep, horses, and goats, but also rabbits and rats. This toxic activity of St. John's Wort was first noted in the literature by Cirillo (1787). The plant, however, does not seem to be a major threat to livestock, because the first symptoms of Hypericum intoxication includes loss of appetite, which makes the absorption of the photodynamic pigment, hypericin, self-limiting.