St. John's wort, also known as Hypericum perforatum, is one of the twelve most commonly used herbs in the United States. This herb has been used for thousands of years and was once used to treat snakebites and ward off evil spirits. Today, St. John's wort is mainly used as a treatment for depression. St. John's wort is the most prescribed antidepressant in Germany and is prescribed more than Prozac. The flowers are pressed to release the oil that is used to make creams or oil extract.
Aerial parts contain tannin, resin, and dye.
The active ingredient is not known. There are 10 constituents that are thought to have the mechanism of action. This fact sheet will discuss some of the claims made about St. John's wort, pros and cons of using it, common dosage, and possible side effects. St. John's wort has been shown to be effective for the treatment of mild to moderate depression. It may increase serotonin levels in the brain, which act to elevate mood and enhance feelings of well-being and satiety.