reserpine, drug derived from the roots of certain species of the tropical plant Rauwolfia. The powdered whole root of the Indian shrub Rauwolfia serpentina historically had been used to treat snakebites, insomnia, hypertension (high blood pressure), and insanity. Reserpine, isolated in 1952, was the first of many Rauwolfia alkaloids found in the crude drug. Because the drug produces a profound and prolonged tranquilizing action, it was once used in treating schizophrenia. Reserpine is sometimes used in treating hypertension, though newer antihypertensive drugs with fewer central nervous system side effects are the preferred treatment.