Methods for the separation of drugs of abuse based on high pressure liquid chromatography have been developed. One of these, a gradient system, can, within 30–40 minutes, separate 16 common street drugs including phencyclidine (PCP), methadone, cocaine, tetrahydrocannabinol (THC), methamphetamine, 2,5-dimethoxy-4-methylamphetamine (STP), methylenedioxyamphetamine (MDA), heroin, N,N-dimethyltryptamine (DMT), lysergic acid diethylamide (LSD), Valium, mescaline, secobarbital, amobarbital, phenobarbital and Dilantin. Adsorption and partition chromatography were both investigated. Adsorption chromatography on Corasil II or Supelcosil-ATF 230 was found to be the most useful and was directly quantifiable. Employment of high pressure liquid chromatography as a preliminary purification to spectral identification of specific drugs was found to be very useful.