It is known that acute strenuous physical exercise may cause diverse pathophysiological consequences in various organs, due to exercise-induced increase in free radical formation. The effect of acute exercise on brain antioxidant system and lipid peroxidation is still unknown. We report here that an acute bout of exercise, which results in several-fold increase of plasma xanthine oxidase activity, does not alter significantly the antioxidant enzyme status of hippocampus and cerebellum, and does not induce lipid peroxidation in those brain regions.