The patterns and pharmacological effects of the nonmedical use of methaqualone (Sopors), a nonbarbiturate sedative-hypnotic, were determined in 66 respondents (median age 22 to 25) residing in Coumbus, Ohio. Sixty percent took this drug at least weekly, with 10% once or more daily. The mean duration of drug use was one year, with 20% in excess of two years. The average single and total daily doses, taken orally, were 530 and 724 mg, respectively; marihuana and alcohol were commonly used concurrently. The major effects of methaqualone use were euphoria, relaxation, and relief from anxieties: paresthesia was frequently reported. About one third of the subjects developed varying degrees of psychological and physical dependence after long-term drug administration. The abuse and complications of acute methaqualone toxicity are reviewed and the relative therapeutic utility of this drug is questioned in view of these major problems.