Objective To investigate the therapeutical effect of triptolide (TP) on subarachnoid hemorrhage (SAH) in rats and its underlying mechanisms.Methods Endovascular perforation technique was used to establish SAH models.TP was used to treat SAH rats by intraperitoneal injection.Rats were randomly divided into control group,SAH 3 d group,SAH 3 d + DMSO group and SAH 3 d + TP group.Pathologic change was observed in rat cortex by HE staining.Cell apoptosis was evaluated by TUNEL assay.Iba-1 considered as microglia marker was assessed by immunohistochemistry.The levels of inflammatory factors including IL-6,IL-1 β and TNF-o were detected by ELISA.Results Compared with control group,pathologic changes,such as cell edema,nuclear pyknosis were more obviously;the number of apoptosis cell,the expression of Iba-1 and the level of inflammatory factors including IL-6,IL-1β and TNF-α were all increased in the cortex of SAH 3 d group,SAH 3 d + DMSO group and SAH 3 d + TP group (P ＜ 0.05).There were no significant differences in pathologic changes,the number of apoptosis cells,the expression of Iba-1 and the levels of inflammatory cytokines in the brain cortex between SAH 3 d group and SAH 3 d + DMSO group (P ＞ 0.05).Compared with SAH 3 d group and SAH 3 d + DMSO group,pathologic changes were alleviated,and the number of apoptosis cells,the expression of Iba-1 and the levels of inflammatory cytokines including IL-6,IL-1β and TNF-α were all decreased in the brain cortex in SAH 3 d + TP group.Conclusion TP could alleviate the pathologic changes,reduce the cell apoptosis and inhibit the microglia activation in rat brain cortex after SAH,and the neuroprotective effect of TP might be associated with the decreased levels of inflammatory cytokines.