Propoxyphene and its major metabolite, norpropoxyphene, have been quantitated in tissue specimens obtained from autopsies of people suspected of dying from propoxyphene overdosage. Gas-chromatographic determination of both propoxyphene and norpropoxyphene is essential because the blood concentration of the parent drug should be about 1.0 mg/liter or greater to attribute a death to the drug. The metabolite concentration in blood may help to establish when the drug was ingested. Concentrations in the blood after high oral therapeutic doses are about 0.3 mg of propoxyphene per liter, and norpropoxyphene concentrations may be as high as 3 mg/liter. Methods of determining propoxyphene are discussed.