Hair analysis can provide evidence of drug use over a much longer period than conventional testing in blood and urine. The incorporation of therapeutic and illicit drugs into human scalp hair may also provide a valuable specimen for determining long-term exposure to drugs. Following sample collection and washing, hair, taken from cadavers known to have ingested psychotropic drugs before death, was either solubilized in sodium hydroxide or treated with dilute hydrochloric acid, methanol, or subtilisin. Digests were treated with a solvent and the extracted drugs were measured using high-performance liquid chromatography. The alkaline digestion procedure was most effective in recovering a range of antidepressant and antipsychotic drugs from hair than any of the other treatments. Application of methanol and subtilisin may allow only 50 percent or less of a psychotropic drug to be detected, but these non-destructive procedures also preserve chemically sensitive molecules of benzodiazepines, cocaine, and heroin. 2 figures, 1 table, and 14 references