Ecstasy (3,4-methylenedioxymethamphetamine or MDMA) is used with increasing frequency as a recreational drug. Accumulated evidence over recent years indicates a growing demand for the drug with a corresponding increase in number of reports of adverse effects from its use. There are reported metabolic disturbances due to MDMA use. These, in addition to the prolonged exercise involved in dancing at 'raves' where MDMA may be used, may exacerbate ketoacidosis. We report two cases of ketoacidosis complicated by MDMA ingestion.