The aim of this study was to evaluate the acute toxicity of the association of energy drink and alcohol in male Wistar rats. Animals were treated by oral gavage with 10ml/kg distilled water (control); 10ml/kg energy drink (ED10); 3.2mg/kg caffeine+40mg/kg taurine; 2g/kg alcohol 20%; 2g/kg alcohol 20%+ED10; and 2g/kg alcohol 20%+3.2mg/kg caffeine+40mg/kg taurine. Behavioral alterations were observed for 6h after treatment. Animals presented significant differences in the frequency of rearing, ambulation, grooming, wakefulness and tachypnea along time. Caffeine+taurine increased the levels of TBARS and total thiols in kidneys. ED10 increased lipoperoxidation in liver. The association of ED10+alcohol induced nephrotoxicity observed by the increase of urinary N-acetyl-β-d-glucosaminidase (NAG) activity. Histopathological analysis showed the presence of congestion and hydropic and hyaline degenerations in the livers of ED10+alcohol treated rats, and hemorrhage in the liver of alcohol+caffeine+taurine group. In kidneys, hyaline degeneration was observed in ED10; ED10+alcohol; caffeine+taurine; and alcohol+caffeine+taurine. Hemorrhage was present in the kidneys of all groups. The combination of energy drinks and alcohol is not safe for the consumers. Therefore, precautionary measures should be disseminated among risk populations, especially the teenagers.