Ferroptosis is a new form of iron-dependent oxidative cell death that is phenotypically distinct from other, more well-understood forms of cell death including apoptosis, autophagy and unregulated necrosis. There are two small molecules know to induce ferroptosis: erastin and RSL3. Both ultimately inactivate glutathione-dependent peroxidases (GPXs) leading to toxic accumulation of reactive oxygen species and, eventually, cell death. We currently identify cells undergoing ferroptosis using BODIPY-C11, a highly generalized fluorescent dye that indicates the production of reactive oxygen species in a lipophilic environment. We hypothesize that ferroptosis has biological implications in numerous diseases and perhaps in development, but lack a direct, efficient way of identifying cells that are undergoing ferroptosis. To test this hypothesis, I plan to identify a dye or antibody that will serve as a selective marker of ferroptosis. With such a probe to reliably detect ferroptosis, we could enable future experiments to examine the mechanism of ferroptosis and its scope in many biological processes.