Book excerpt: The goal of this text is to focus readers attention on three major areas; the origin and localization of GSH in the nervous system; the multiple effects of GSH on neural health activity; and the potential for alterations on GSH status to lead to neurological damage of the type observed in amyotrophic lateral sclerosis, Parkinson's disease and other neurological disorders. The text also touches upon the additional roles of the antoxidant GSH, including possible neurotransmitter action, redox modulation of ionotropic receptor function, and neuroprotection against exicitoxic actions of glutamate.