This article describes the acute & chronic toxic effects of the amphetamine derivative ecstasy. The detailed review of the literature presents 87 ecstasy-related fatalities caused by hyperpyrexia, rhabdomyolysis, intravascular coagulopathy, hepatic necrosis, cardiac arrhythmias, cerebrovascular accidents, accidents, & suicide. The available evidence does not yet permit an accurate assessment of the size of the problem presented by the use of these drugs. (191 refs) (SC)