We have previously proposed a novel EPO-derived short peptide, MK-X, which has a neuroprotective effect against oxidative stress without adverse side effects characteristic of EPO such as unwanted cell proliferation.41 In this study, we examined the neuroprotective effect of MK-X in comparison with that of EPO against glutamate-induced excitotoxicity induced in vitro in cultured neurons and against brain injury in an in vivo stroke model. Here, EPO is linked to stroke disorder.