Alzheimer's disease is a devastating degenerative disorder of the brain for which there is no cure or effective treatment. Although the etiology of Alzheimer's disease is not fully understood, recent research suggests that deposition of cerebral amyloid plaques is central to the disease process. Therefore, an attractive therapeutic strategy for Alzheimer's disease is to prevent, reduce or reverse amyloid deposition in the brain. Several small chemical compounds, synthetic peptides and natural proteins have been described that inhibit amyloid formation or amyloid neurotoxicity in vitro. The effect of these and other compounds now needs to be tested in vivo and the ability of amyloid inhibitors to halt the progression of Alzheimer's disease in humans needs to be evaluated.