We evaluated the ability of fluoxetine, an inhibitor of serotonin uptake, and Ca-acetyl-homotaurinate, a GABAergic derivative of taurine, to counteract ethanol intake in familial and nonfamilial alcoholic patients. Fluoxetine, homotaurinate, or placebo were administered for 1 month each, in random order, to both groups of patients. The mean number of alcoholic drinks were measured during the 2 weeks before treatment (baseline) and during the 3 months of treatment. The nonfamilial alcoholic patients showed a slight response to fluoxetine; however, the mean number of alcoholic drinks significantly decreased (P < 0.05) during the homotaurinate treatment. In contrast, the familial alcoholic patients showed a significant decrease in ethanol intake (P < 0.05) after fluoxetine therapy and no effect after homotaurinate treatment. Our findings support the hypothesis that monoaminergic underactivity is present in familial alcoholic patients and suggest the possibility of specific chronic treatment of alcohol addiction related to preexisting personality disorders.