Our auto-addiction model suggests that opiate blockade may be therapeutically useful in anorexia nervosa and bulimia nervosa. Naltrexone was administered to out-patient subjects in double-blind clinical trials with randomized cross-over designs. Reduction in binge-purge symptomatology was evident in the naltrexone period over placebo for 18 out of 19 subjects with either bulimia or anorexia nervosa of the bulimic subtype. In every case, the decoding of drug or placebo double blinding confirmed the assessments of both the investigator and the subjects, based on the blind analysis of the data and on their therapeutic response, respectively. Statistical analysis done on the total population and two diagnostic subgroups found highly significant differences.