Numerous studies have shown that the generation of C5a and its interaction with the receptor C5aR1 played a deleterious role in multiple diseases, including atherosclerosis, arthritis, renal ischemia-reperfusion injury, small intestine ischemia-reperfusion injury, mesenteric ischemia, myocardial ischemia, and ischemic stroke [272, 279-284]. This evidence concerns the gene C5AR1 and ischemic stroke.