Hypericum perforatum 

St. John’s Wort and other plants that have St. John as part of their common name are so called because they can be relied upon on to be in bloom on June 24, the feast day of St. John the Baptist.

Extracts made from the blossoms of St. John’s Wort have been used for centuries to treat mental disorders and to ward off evil spirits. American Indians treated tuberculosis, wounds, and severe pain with a tea made from its flowers. Hypericin, a very complex molecule, is of questionable value in the treatment of mild depression; it is strongly antiviral and is being investigated for use in the treatment of HIV/AIDS.