Abstract： Objective To evaluate the protective effect of sinomenine (SIN) on renal ischemia/reperfusion (I/R) in mice. Methods In the experiment one, 12 C57BL/6 mice were randomly divided into 2 groups: SIN group (mice were injected with 200 mg/kg SIN by tail vein) and control group (mice were injected with equal volume of saline). Six and 24 hs later, the serum was collected and the contents of alanine aminotransferase (ALT) and creatinine (SCr) were determined. In the experiment two, C57BL/6 mice were randomly divided into 3 groups: sham-operated (SO) group, SIN group (mice were injected with 200 mg/kg sinomenine just before ischemia induction) and saline group (mice were injected with equal volume of saline at the same time). At the 6th h after reperfusion, the sera and renal samples subject to IR injury were collected. The SCr and BUN levels in serum were determined and renal histological changes were also examined. The apoptosis of renal tubular epithelial cells was measured by using terminal deoxynucleotidyl transferase mediated dUTP nick end labeling assay. The infiltration of F4/80 positive macrophages was measured by using immunohistochemistry and that of neutrophils with myeloperoxidase (MPO) kits. The mRNA expression of tumor necrosis factor (TNF)-α, chemokine CXC ligand (CXCL)-10, intercellular adhesion molecule (ICAM)-1 and IL-17 was detected by using real-time reverse transcription PCR. The activation of transcription factor NF-κB was measured by using Western blotting. Results In the experiment one, there was no significant difference in ALT and SCr between the two groups at 6 or 24 h. In the experiment two,levels of SCr and BUN were lower in SIN group (P＜0. 05 or P＜0. 01 ), histological damage was milder (P＜0. 01 ), and apoptosis rate of renal tubular epithelial cells apoptosis was lower than in saline group (P＜0. 05). The infiltration of macrophages, neutrophils and the mRNA expression of TNF-α, CXCL-10, ICAM-1 and IL-17 in the renal tissue in SIN group were reduced as compared with saline group (P＜0. 05 or P＜0. 01 ). The activation of NF-κB in SIN group was significantly downregulated as compared with saline group. Conclusion SIN can ameliorate the renal IR injury without hepatic or renal toxicity, which is associated with inhibition of acute inflammatory response induced by reperfusion.