Alzheimer's disease is characterized by signs of a major oxidative stress in the neocortex and the concomitant deposition of Amyloid beta (Abeta). Abeta is a metalloprotein that binds copper, and is electrochemically active. Abeta converts molecular oxygen into hydrogen peroxide by reducing copper or iron, and this may lead to Fenton chemistry. Hydrogen peroxide is a freely permeable prooxidant that may be responsible for many of the oxidative adducts that form in the Alzheimer-affected brain. The electrochemical activity of various Abeta species correlates with the peptides' neurotoxicity in cell culture, and participation in the neuropathology of Alzheimer's disease. These reactions present a novel target for Alzheimer therapeutics.