St. John’s wort, or hypericum perforatum, is a perennial herb that originated in Europe. It produces oval-shaped green leaves and yellow flowers with five petals. This hardy plant grows so abundantly that it can be classified as a weed when it springs up in unwanted locations. Due to its popularity as a natural supplement, St. John’s wort is cultivated in many countries, including the US and Australia. St. John’s wort has been used in traditional European medicine for thousands of years to alleviate nervous disorders. It has also been applied topically to burns and wounds. Modern clinical studies support these traditional uses.