This flowering perennial herb is native to many temperate areas of the word, and is grown commercially in parts of south east Europe. You can find it growing wild in many parts around the globe--the Americas, Australia, India and even parts of Africa, to name a few.
The yellow flowers typically appear around June 24th, the feast day of St. John the Baptist, thus the name. Wort is an Old English word which means, "plant."
St. John's Wort is probably most popular for it's use in treatment of depression and mood disorders. Long before this use was discovered however, the plant was used in herbal medicine to treat wounds, burns and muscle pain. It is anti-inflammatory, anti-bacterial and anti-microbial.