The hair was prepared in a decontamination procedure in dichloromethane at 37 degrees C for 15 minutes, solubilization in sodium hydroxyde at 100 degrees C for 5 minutes, neutralization with hydrochloric acid, and centrifugation. After extraction in chloroform-isopropanol-n-heptane at pH 9.2, drugs were derived with BSTFA and 1 percent TMCS and separated on a 12-m BP-5 capillary column. Quantification was performed using gas chromatography/mass spectrometry (GC/MS), utilizing selected ion monitoring. The highest morphine concentrations were found in pubic hair, then head hair and axillary hair. Codeine was also detected in all hair samples. The authors suggest that the concentration of drugs in head hair collected from the posterior vortex provides a good historical record of drug use; however, estimates based on analysis of pubic hair may be high, while estimates based on analysis of axillary hair may be low. 1 table, 1 figure, and 20 references