Most previous studies have showed that the cytotoxic effect of proteins(including major basic protein (MBP), eosinophil peroxidase (EPOX), eosinophil cationic protein (ECP), and eosinophil-derived neurotoxin (EDN)) released by circulating eosinophils, thrombus formation, and endothelial damage are causes of brain infarction. This evidence concerns the gene RNASE2 and brain infarction.