Erythropoietin (EPO) is a cytokine originally identified for its role in erythropoiesis and more recently shown to be produced in the central nervous system.Relative insufficiency of endogenous EPO during periods of ischemic stress may trigger neuronal apoptosis, whereas the provision of exogenous EPO has been shown to inhibit this process. The potential immediate protective effects of EPO include decreased NO production, activation of antioxidant enzymes, reduction of glutamate toxicity, inhibition of lipid peroxidation, and reduction of inflammation. Long-term protective effects of EPO include the generation of neuronal anti-apoptotic mechanisms, stimulation of angiogenesis, and modulation of neurogenesis.