Oxidative stress is known to play a critical role in the pathogenesis of various disorders, especially in ischemia/reperfusion (I/R) injury. We identified an apoptosis-inducing humoral factor and named this novel post translationally modified secreted form of eukaryotic translation initiation factor 5A (eIF5A) “oxidative stress-responsive apoptosis inducing protein” (ORAIP). The purpose of this study was to investigate the role of ORAIP in the mechanisms of cerebral I/R injury.