Abstract: OBJECTIVE To investigate the effect of 5,7-dihydroxyl-8-nitrio chrysin(8-NOChR) combination with cisplatin(DDP) on the growth of human ovarian carcinoma COC1 cells xenografts in nude mice. METHODS Models of human ovarian cancer COC1 cells xenografts transplanted subcutaneously in nude mice were established, and randomly divided into four groups: saline group, 8-NOChR group, DDP group, 8-NOChR combination with DDP group. Tumor volume, tumor weight and the weight of nude mice were measured. The serum levels of LDH, ALT, Cr and WBC counts were determined. The rate of apoptotic cells of human ovarian carcinoma COC1 cells xenografts was analyzed by PI stained FCM. The expressions of bcl-2 protein and caspase-3 protein of COC1 cells xenografts were determined by Western blot. RESULTS There were significant difference in tumor volume and tumor weight between the nude mice treated with 8-NOChR combined with DDP and those treated with 8-NOChR or DDP(P<0.05). There were no difference in the weight of nude mice and in the serum levels of LDH, ALT, Cr and WBC number in the nude mice treated 8-NOChR combined with DDP comparing with those treated with DDP(P>0.05). The xenografts cells treated with 8-NOChR combined with DDP showed apoptosis. Western blot showed that expression of caspase-3 protein was upregulated and protein level of bcl-2 was depressed after treatment with 8-NOChR combined with DDP. CONCLUSION 8-NOChR and DDP have synergistic effects on the growth inhibition of human ovarian carcinoma COC1 cells xenografts in nude mice. Mechanism may be downregulation of bcl-2 expression and activation of caspase-3 expression