Abstract: OBJECTIVE To investigate the effect of Danhong injection on aldose reductase(AR) expression in hippocampal CA1 of cerebral ischemia-reperfusion rats, and to reveal the protective mechanism. METHODS SD rats were randomly divided into sham operation group, ischemia-reperfusion group(model group), ischemia-reperfusion with Danhong injection group(Danhong injection group), ischemia-reperfusion with epalrestat group(epalrestat group). One hour reperfusion model of middle cerebral artery ischemia by modified suture method. At the beginning of cerebral ischemia-reperfusion in rats, the Danhong injection group and the epalrestat group were administered in travenously with dose of 2 mL·kg^-1, 20 μg·kg^-1 at 0, 24, 48 h. Then, the rats were sacrificed 72 h later. HE staining, immunohistochemistry and Western blot were used to evaluate the pathological changes of neurons, the AR positive index and expression level of AR in hippocampal CA1. RESULTS After 72 h of administration, compared with the sham group, the hippocampal CA1 displayed disordered neurons arrangement and significant apoptosis in the model group. Western blot showed that the expression of AR was significantly increased after cerebral ischemia-reperfusion(P<0.05). Compared with the model group, the Danhong injection group and epalrestat group exhibited less neuronal apoptosis and more regular neurons distribution. The AR positive index of Danhong injection group was decreased(P<0.05). Western blot showed that the expression of AR was also inhibited by Danhong injection. CONCLUSION Ischemia-reperfusion injury induced the expression of AR in hippocampal CA1. Danhong injection has protective effects on hippocampal CA1 neuronal cells via down-regulating the expression of AR.