A three-year review of toxicology data from medical examiner autopsies in Pima County, Arizona, has demonstrated that cocaine has rapidly become a leading substance of abuse, second only to alcohol in the frequency of drugs detected by toxicologic analysis of all suspicious deaths, motor vehicle accident fatalities, homicides, and suicides. Gastric contents and urine were analyzed by thin-layer chromatography, and nasal swabs, blood, and urine were tested for the combination of cocaine and its metabolite benzoylecgonine by quantitative radioimmunoassay. A total of seventy-two deaths in Pima County from 1982 to 1984 have involved cocaine. Seventy percent of these have occurred in the last fifteen months. Marked variation in the individual response to cocaine compared to the blood concentration of cocaine/metabolite was noted.