The authors suggest use of the fluorescence polarization immunoassay (FPIA) technique in evaluation of chronic drug abuse using human hair. Hair was decontaminated in 5 mL of ethanol for 15 min at 37 degrees C and then incubated in 3 mL of 1M sodium hydroxide (NaOH) for 1 h at 100 degrees C. Afterwards, the aliquots were neutralized and analyzed using Abbott ADx for a negative or positive response for the following drugs: benzodiazepines, barbiturates, antidepressants, opiates, cocaine, amphetamine, and cannabis. All the positive samples were confirmed by gas chromatography/mass spectrometry (GC/MS). Only one false positive was detected (caused by interference of a phenothiazine with the antidepressants kit), clearly demonstrating the capability of ADx for toxicological screening of human hair.