We found that the expression of IL-17 in the ischemic cortex and hippocampus of stroke mice treated with As IV was decreased remarkably by both immunohistochemistry and Western blot analysis (Figures 3A, B) and the expression of IL-17 increased gradually and slowly after stroke as time went on and lagged far behind the appearance of apoptosis (Figure 3C). This evidence concerns the gene IL17A and Stroke.