Students of narcotic addiction have believed that heroin addiction is more debilitating than the "traditional" opium addiction. Access to both opium and heroin addicts in a Laotian treatment facility provided an opportunity to test this hypothesis. All subjects were volunteer narcotic addicts seeking treatment at an inpatient detoxification facility over a 12-month period. The research format consisted of five demographic characteristics, four aspects of past narcotic usage, and three aspects of current narcotic usage. Fifty-one heroin addicts were compared to 438 opium addicts. Many of the demographic differences in the two groups reflected the urban residence of most heroin addicts and the mixed urban-rural residence of opium addicts. Heroin addicts had more frequent daily doses of drug, spent considerably more money for their drug, and required higher initial methadone doses for detoxification. It also appeared that heroin addicts might have "deteriorated" faster and thus sought treatment earlier than opium addicts. Since the heroin and opium addicts in this study differed significantly on most demographic characteristics, it was difficult to know whether these observed differences were due to drug factors or demographic factors. Thus, a study of pairs matched for age, sex, and ethnicity was subsequently undertaken to test the hypotheses generated by this study.