Gamma-hydroxybutyric acid (GHB) is an endogenous constituent of the mammalian brain, where it likely functions as a neurotransmitter or a neuromodulator. Its exogenous administration exerts a number of pharmacological effects, including reduction of intensity of alcohol withdrawal syndrome and alcohol consumption in both laboratory animals and human alcoholics.The clinical studies conducted to date, although often testing samples of limited size, feature GHB as an effective, well-tolerated and safe drug for the treatment of alcohol dependence. Behavioural data in rats suggest that GHB may produce alcohol-like effects. This similarity may explain why GHB produces positively reinforcing properties, being subsequently self-administered by rodents and sometimes abused by humans (although episodes of self-directed intake of GHB appear to be a limited phenomenon in alcoholics); in addition it provides support to the hypothesis that GHB constitutes for alcoholism a replacement therapy similar to methadone in heroin addiction.