Ever since inflammatory mediators were detected in and around amyloid plaques in the brain of patients with Alzheimer's disease, there has been great interest in the inflammatory hypothesis and the possibility of treating Alzheimer's disease with anti-inflammatory drugs. Various epidemiological studies have now demonstrated that the use of nonsteroidal anti-inflammatory drugs (NSAIDs) is indeed associated with a reduced risk of developing Alzheimer's disease. The effect of NSAIDs in Alzheimer's disease is probably mediated by activation of the peroxisome proliferator-activated receptor-gamma. Administration of NSAIDs in a mouse model of Alzheimer's disease appears to suppress amyloid plaque formation and inflammatory mediators. These findings suggest that NSAIDs may also be able to slow down Alzheimer's disease progression. So far, only one small clinical trial has shown that treatment with NSAIDs significantly delayed cognitive decline in Alzheimer's disease patients. Large randomized double-blind placebo-controlled trials are needed to provide definitive evidence that NSAIDs have a therapeutic effect on Alzheimer's disease.