Sixty cases of methaqualone ingestion have been reviewed from 1977 through 1980. Serum methaqualone concentrations, clinical information, and demographic data were studied in order to define the present status of abuse of this drug. The average user was a 27 year-old man who ingested Quaalude plus at least one additional drug (usually a narcotic analgesic, ethanol, a benzodiazepine, or a barbiturate, in that order). He was admitted to the emergency room with a depressed level of consciousness and a serum methaqualone concentration of 5 +/- 3 mg/L (mean +/- SD). Following a brief period of observation and supportive care, he was discharged from the hospital. Serum methaqualone concentrations showed no significant correlation with the physical findings, except that levels greater than or equal to 9 mg/L were always associated with a depressed level of consciousness, whether or not other drugs were present. Despite strict federal controls, methaqualone abuse appears to be a continuing problem, and analysis for this drug should be part of the toxicology screen.