The recent investigations on biochemical and biophysical mechanisms of ethanol in acute intoxication, tolerance and physical dependence suggest that the cell membrane, intracellular metabolism and central neurotransmitters are involved. In acute intoxication ethanol increases the "fluidity" of the cell membrane and stimulates the central gabergic system. In alcoholics, the body adapts, and in the presence of ethanol, the cell membrane becomes more "rigid" and the gabergic system hypoactive. When alcohol intake is discontinued the hypoactivity of the gabergic system is unmasked and it is manifested as withdrawal syndrome. The alcohol intake compensates for the clinical symptoms of decreased gabergic activity and thereby continuously prevent the onset of withdrawal symptoms. On the other hand, intact central noradrenergic and 5-hydroxytryptaminergic systems as well as the neuropeptide vasopressin maintain the tolerance. After withdrawal syndrome, membrane alterations and the state of diminished gabergic activity gradually return to normal. This period of slow recuperation corresponds to the subacute withdrawal syndrome. In this period, there is a continuous desire for alcohol intake. Further, alcoholics, in this situation, are very vulnerable with feelings of insecurity, fragility and isolation. All these factors additionally induce a latent desire for ethanol. It follows then that a stimulation of decreased gabergic activity is a new approach in drug therapy of alcoholism. One of these new stimulants is acamprosate. The new substance is a structural analogue of GABA and acts as an agonist on gabergic receptors. Therefore, acamprosate improves the central gabergic activity. Alcoholics treated with acamprosate stated that they no longer felt a desire for alcohol intake. In this way, acamprosate maintains the abstinence for several months during the post-withdrawal phase.(ABSTRACT TRUNCATED AT 250 WORDS)