Impaired neuroprotection resulting from oxidative stress has been implicated in neurodegeneration in a number of pathologic conditions of the brain, including both subcortical and cortical type dementias. Production of excessive oxidative stress, moreover, can lead to elevated levels of certain proinflammatory cytokines that are considered to be contributing factors to neuronal injury and are evident in HIV-related dementia as well as in other neurodegenerative conditions. Inhibitors of oxidative damage could thus be promising therapeutic agents for preventing progressive nerve cell death and slowing the advance of neurodegenerative disease. The potential of antioxidant therapy to provide neuroprotection is substantiated by studies demonstrating reduced oxidative stress with supplementation and lower risk for cognitive impairment with higher plasma antioxidant levels.