Multivesicular bodies (MVBs) with diameters up to 4.5 microns were observed in the hippocampal pyramidal cells of rats submitted to chronic alcohol consumption. A significant increase in the volumetric density (Vv) of these organelles was found in CA1 pyramidal cells. Transitional forms of MVBs towards lysosomes were seen. A failure in MVB's enzymatic hydrolytic mechanisms, due to the prolonged alcohol aggression, could underlie its formation.