The present invention provide a method for the prevention and treatment of a neurodegenerative disease including Alzheimer's Disease, Huntington's Disease, and Parkinson's Disease, using a grape seed extract or one or more compounds derived therefrom. In particular, the present invention provides a method to treat a patient diagnosed with, or at the risk of developing, a neurodegenerative disease by administering a pharmaceutical composition comprising a grape seed extract or one or more compounds derived therefrom to the patient in a therapeutic amount to reduce the accumulation, aggregation or deposition of amyloid beta or its oligomers, and/or to reduce the misfolding, accumulation and/or aggregation of tau proteins or other proteins.