All cases of homicide in which the victim was over 15 years of age were included in the analysis. Toxicology procedures were used to detect lower alcohols, alkaline drugs, acidic and neutral drugs, opiates, and cocaine and cocaine metabolites. When urine was available, screening was performed by fluorescence polarization immunoassay. Cannabinoids were measured in blood by a gas chromatography/mass spectrometry (GC/MS) procedure. All drugs positive on screening were then confirmed and quantitated in blood by GC/MS. A high positivity rate for drugs and/or alcohol, ranging from 66 to 73 percent, was found for each year. Alcohol, present in more than half the cases, ranged from 54.2 to 60.3 percent. The detection of cocaine or cocaine metabolites increased drastically during the study period, from 1.6 percent of cases in 1985 to 18.7 percent in 1991. Heroin metabolites, indicative of recent heroin use, were detected in only 2 to 5 percent of the cases in each year studied. Drugs other than alcohol, cocaine, and heroin were detected in 7 to 25 percent of the cases. 17 references and 2 tables