BOSTON, MASSACHUSETTS. St. John's Wort is a popular and powerful herb which has been found highly effective in combating depression. It is particularly popular in Germany where prescriptions for 66 million daily doses were issued in 1994 alone. Very few side effects have been reported, but caution is advised when switching to or from pharmaceutical antidepressants. Most St. John's Wort products also carry a warning about avoiding excessive sunlight exposure. Dr. Geoffrey Bove of the Beth Israel Deaconess Medical Center now reports a case of a 35-year-old woman who developed severe pain in her face, hands, arms, and legs while taking St. John's Wort (500 mg/day of a whole ground product) for a mild depression. The stinging pain developed spontaneously with a light touch, air movement or exposure to cold and was particularly bad after sun exposure. The pain gradually disappeared over a two-month period once she stopped taking the St. John's Wort. Dr. Bove ascribes the development of the exaggerated pain sensitivity to the St. John's Wort and cautions physicians to be aware of this possibility in patients diagnosed with toxic neuropathy.