A feasibility demonstration with a gas chromatograph/mass spectrometer/computer system (GC/MS) was initiated to provide a 24-hour (seven days/week) adjunct emergency toxicology service to the hospitals in the tricounty area comprising Metropolitan Detroit. During June 1, 1974, to April 1, 1975, more than 85 different drugs and other agents were identified in the body fluids of approximately 1,000 victims of accidental or deliberate poisonings. At least one toxic substance was identified in 57% of the cases, and the presence of two or more drugs was established in one of five (19%) of the victims. This study indicates that a centrally located GC/MS/computer system can provide an effective adjunct emergency toxicology service for an entire metropolitan community and thereby provide guidelines for a prompt and rational therapy.