Ecstasy is the common name for a synthetic drug that has stimulant and hallucinogenic properties. Taken in pill form, it is commonly used at large, all-night dance parties known as raves. The drug produces feelings of relaxation, decreased anxiety, and heightened senses. Ecstasy also causes muscle tension, increased heart rate and blood pressure, and sweating. These symptoms, when combined with the vigorous physical activity of dancing, can lead to severe dehydration, heart or kidney failure, and even death. Ecstasy is also known as MDMA, for its chemical name, 3-4 methylenedioxymethamphetamine.