There are no significantly effective therapeutic or prophylactic agents for Alzheimer's disease (AD), the leading cause of age-related dementia. AD is characterised pathologically by plaque-like deposits of beta-amyloid in the brain as well as cytoskeletal ("neurofibrillary") alterations within nerve cells. A novel immunisation strategy directed at the beta-amyloid abnormalities underlying plaque pathology has recently been proposed for AD. This approach is supported by experimental studies utilising beta-amyloid as an immunogen, or antibodies to beta-amyloid, in transgenic experimental models that develop plaque pathology but not neurofibrillary alterations or severe neurodegeneration. Behavioural abnormalities in these mice related to deficits in spatial working memory were also ameliorated by immunisation with beta-amyloid. The promise of this novel approach to AD treatment and/or prevention has led to initial human trials utilising beta-amyloid as an immunogen.