A cell-permeable necrosis inhibitor that displays antioxidant property. It localizes mostly in the mitochondria. Selectively blocks oxidative stress-induced necrotic cell death (0.1 µM NecroX-5 prevented ~50% cell death in H9C2 cells exposed to 400 µM t-BuOOH for 2 hours). Does not protect against staurosporine or etoposide-induced apoptosis. Protects cells against cold shock, hypoxia and oxidative stress in vitro, as well as CCl4 -induced acute liver injury and chronic liver fibrosis in rodent models.