The use of antagonist drugs to reduce the duration of opiate detoxification severely enhances withdrawal symptoms. To investigate the feasibility of administering antagonists with opiates without intense withdrawal during detoxification, 5 methadone maintained patients were evaluated while tapering methadone and receiving at the same time very low (0.125 mg), then increasing daily doses of naltrexone in the course of a 6-day, day hospital treatment. Reduced quantities of adjunctive medications were administered, as compared to the standard protocols, the treatment was completed without incidents or particular discomfort and all patients were easily induced to naltrexone maintenance by the day of discharge. Controlled studies will clarify whether very low-dose naltrexone provides a safe and comfortable detoxification technique to reduce withdrawal intensity and duration without the problems of heavy sedation, as suggested by the description of these clinical cases.