Cl-Necrostatin-1 is an inhibitor of receptor-interacting protein kinase 1 (RIPK1). It inhibits RIPK1 activity when used at concentrations of 0.3, 3, and 30 µM. It also inhibits TNF-α-induced necroptosis in Jurkat cells deficient in Fas-associated death domain protein (FADD; EC50 = 180 nM), a modification that prevents caspase activation in response to death-domain receptor signaling. Cl-Necrostatin-1 (2 µl of a 4 mM solution, i.c.v.) reduces infarct size when administered pre- and post-occlusion, or post-occlusion only, in a mouse model of middle cerebral artery occlusion (MCAO).