Cyanamide, a disulfiram-like drug used in the treatment of alcoholism, decreased in a dose-dependent manner (2-25 mg/kg) the body weight gain curve in rats, which resulted in a marked decrease of body weight (10-35%). Long-term administration of cyanamide also decreased food intake (6-34%) in a dose-dependent manner (2-25 mg/kg). Both effects of cyanamide were reversible. After the acute and long-term administration (1-12 months) of cyanamide (8-35 mg/kg) the brain concentration of 3-methoxy-4-hydroxyphenylethyleneglycol sulphate (MOPEG-SO4) was also significantly increased (26-46%). Cyanamide, however, had no effects on the brain concentration of noradrenaline, dopamine, 5-hydroxytryptamine, tryptophan and 5-hydroxyindolacetic acid. It is suggested that the loss of weight, the decrease in food intake and the increase in brain MOPEG-SO4 induced by cyanamide reflect possible anorectic properties of the drug.