Research of the alcohol action mechanism on the SNC in acute alcoholic intoxication (AAI) has been dealt in various ways. On one side the alcohol action--apparently most unspecific--on cellular membranes has been studied. Other authors, instead, have studied more specific alcohol effects on three types of neurotransmitters: opioid peptides, GABA and catecholamines. The effect of alcohol on cellular membranes seems to be beyond any doubt. Alcohol action on specific neurotransmitters is the object of controversy, especially in the case of endogenous opioids. There are data which strongly support the participation of the GABA receptors in the AAI. Modifications produced in the cellular membrane by alcohol action can modify the structure of the function of the membrane receptors. On the other hand, distinct receptors may be localized in the same neuron, while the existence of interactions between different neurotransmitters is well known. Therefore, the various hypotheses previously stated are not mutually exclusive.