Used for centuries to treat everything from burns and wounds to malaria and sleep disorders, St. John’s wort is perhaps best known as a treatment for mild to moderate depression. While it is not prescribed for such purposes in the United States, it is widely prescribed to treat less-severe depression in Europe, an area of the world that has also conducted a couple of dozen studies on the herb that back up its reputation as an effective mild/moderate antidepressant. A recent study published in the online edition of The British Medical Journal seems to indicate that St. John’s wort can also be effective in treating more severe depression, with many fewer side effects than traditional antidepressant medications.