Alcohol was the most widely detected drug, present in 85 percent of the cases studied. Seventy percent of the suspects and 45 percent of the victims had alcohol present. Cocaine was the second most used drug and was detected together with its metabolite benzoylecgonine in 30 percent of the cases. As with alcohol, more suspects (30 percent) than victims (15 percent) had alcohol detected. The combination of alcohol and cocaine (and benzoylecgonine) was present in 20 percent of the cases. Tetrahydrocannabinol was detected in one suspect and methamphetamine in one victim, each in combination with other drugs. Data on the drug status of the suspect and victim indicate that in 95 percent of the cases drugs were found in either the suspect, the victim, or both. With the availability of precise toxicological identification of alcohol or drug use, the criminal justice system can respond properly and aggressively when confronted with a domestic violence problem by mandatory arrest and collection of samples for drug analyses. 3 tables and 25 references (Author abstract modified)