Accumulation of amyloid‐β(Aβ) in the brain is a major cause of dementia in Alzheimer's disease.In this article,Dr de Silva,Dr Carare and ProfessorWeller review the mechanisms for the elimination of Aβ from the brain,the reasons why these mechanisms fail in Alzheimer's disease,and how understanding this failure may lead to new approaches to the treatment of Alzheimer's disease. Copyright © 2008 Wiley Interface Ltd