In Alzheimer's disease (AD), nerve cells and their connections are lost, leaving the brain unable to function normally. The nerve cell loss is associated with the production of ß-amyloid peptide, which accumulates in the brains of patients with AD. ß-amyloid peptide is produced from the larger ß-amyloid precursor protein (APP) when the precursor is cut by specific enzymes called proteases. It has recently been discovered that this same precursor molecule (APP) also gives rise to a second cell death molecule that is actually more toxic than the ß-amyloid peptide. This new molecule is called C31 and is also produced in the brains of patients with AD. In laboratory experiments where the production of C31 from APP is blocked, the degree of cell death can be reduced dramatically. For these reasons, it is believed that the development of drugs that prevent C31 generation in AD is very important and presents a new therapeutic angle to treat AD.