Alzheimer's disease is one of the most challenging brain disorders and has profound medical and social consequences. It affects approximately 15 million persons worldwide, and many more family members and care givers are touched by the disease. The initiating molecular event(s) is not known, and its pathophysiology is highly complex. However, free radical injury appears to be a fundamental process contributing to the neuronal death seen in the disorder, and this hypothesis is supported by many (although not all) studies using surrogate markers of oxidative damage. In vitro and animal studies suggest that various compounds with antioxidant ability can attenuate the oxidative stress induced by beta-amyloid. Recently, clinical trials have demonstrated potential benefits from treatment with the antioxidants, vitamin E, selegiline, extract of Gingko biloba, and idebenone. Further studies are warranted to confirm these findings and explore the optimum timing and antioxidant combination of such treatments in this therapeutically frustrating disease.