Abstract: A convincing link between oxidative stress and neurodegenerative diseases has been found with the knowledge that it actually damages neuronal cells in culture. We analyzed the effect of dl-α-lipoic acid on lipofuscin and Na+K+ ATPase in discrete brain regions of young and aged rats. In aged rats, the level of lipofuscin was increased, and the activity of Na+K+ATPase was decreased. Intraperitoneal administration of lipoic acid to aged rats led to a duration-dependent reduction and elevation in lipofuscin and enzyme activity, respectively, in the cortex, cerebellum, striatum, hippocampus, and hypothalamus of the brain. These results suggest that lipoic acid, a natural metabolic antioxidant, should be useful as a therapeutic tool in preventing neuronal dysfunction in aged individuals.