Alprazolam is a commonly prescribed benzodiazepine. The abuse of benzodiazepines is most frequently seen in conjunction with the abuse of other drugs. Only rare fatalities have been attributed to alprazolam alone. We undertook a retrospective review of cases investigated by the Palm Beach County Medical Examiner's Office in which postmortem toxicologic studies indicated the presence of alprazolam, to further study the pattern of alprazolam abuse. Our review consisted of 178 cases, including 87 in which death was attributed to combined drug toxicity, 2 to alprazolam toxicity alone, 44 to trauma, 12 to natural causes, and 33 to another drug or drugs. Cocaine and methadone were the most common cointoxicants in the cases of combined drug toxicity, while heroin was less frequently detected. There was considerable overlap in the postmortem blood alprazolam concentrations among the groups. The overlapping ranges of concentrations of alprazolam detected indicate that it may be difficult to define a lethal alprazolam range, and that it may not be possible to determine the actual role of alprazolam as a causal factor in cases of combined drug toxicity. This study confirms that alprazolam alone is rarely a cause of death, and that alprazolam abuse usually occurs within a polydrug use pattern. The high incidence of cocaine as a cointoxicant has not been previously reported.