The street drug samples were all in powder form. The analysis also considered samples taken from 9 packets and 22 syringes found beside corpses. The study focused on the composition of the drug and the accompanying adulterants and diluents. Just over 63 percent of the street drug samples contained heroin, 12.5 percent cocaine, 8.5 percent amphetamine, and 15.4 percent other substances. The concentration of heroin ranged from 21 to 60 percent in most of the heroin inclusive samples. Similar concentrations of cocaine were found in the samples containing that substance. Adulterants were detected in 78.8 percent of the samples containing heroin, 59.6 percent of the samples containing cocaine, and 56 percent of the samples containing amphetamine. The most common adulterants in the samples containing heroin were caffeine (68.4 percent), phenobarbital (19.7 percent), methaqualone (13.4 percent), and procaine (13.4 percent), while lidocaine was the most common adulterant (52 percent) in the samples containing cocaine. Tables and 11 references. (Author abstract modified)