{description}Apoptosis is a normal physiological process of programmed cell death or “cell suicide” that eliminates damaged or stressed cells. Errors in apoptosis are involved in approximately 70% of human diseases including cancer, Parkinson’s, Alzheimer’s, and the massive cell death that occurs after a heart attack or stroke. The caspases, a family of enzymes that break down proteins, are key players in the apoptosis program, but few tools are available to study caspase activity. However, in the August 18, 2006 issue of Molecular Cell, a team of researchers, including the author of this article, from the lab of Dr. Matthew Bogyo in the Pathology Department of the School of Medicine described the synthesis of novel tools called Activity Based Inhibitors and Probes (ABIs and ABPs) that can be used to inhibit and track caspase activity. ABIs and ABPs are helping researchers understand apoptosis, and may help to diagnose and develop therapeutics to treat diseases that result from aberrant apoptosis. {/description}