Aim To study the effect of Astragalus injection on tumor growth inhibition of human nasopharyngeal carcinoma cell strain CNE2 xenograft in BALB/c nude mice,and explore the possible mechanisms.Methods CNE2 cells were injected subcutaneously into nude mice to establish model of transplanted tumor.Twenty one model nude mice were divided randomly into three groups treated with intraperitoneal injection,viz the model group given normal saline 10 ?l?(g?d)~-1,the positive control group given Cisplatin 30 mg?m~-2 every fourteen days and given normal saline sodium 10 ?l?(g?d)~-1 in other days,and the treatment group given Astragalus injection 10.40 mg?(g?d)~-1.The above administrations for groups lasted 4 weeks.The inhibitory effect of Astragalus injection on the growth of tumors in nude mice was observed,and the inhibitory rate and the relative tumor proliferation rate were calculated.The expression levels of p53 mRNA in tumor tissues were determined by FQ-PCR.Results After four weeks′treatment,the volumes of tumors in nude mice from the model group,the Cisplatin group,the Astragalus injection group were(1.51?0.25)cm~3,(0.91?0.35)cm~3 and(1.04?0.51)cm~3 respectively.Compared with the model group,the tumor volumes in the Cisplatin group and in the Astragalus injection group were smaller(P0.05).Conclusions The results suggest that Astragalus injection shows inhibitory effect on the growth of human nasopharyngeal carcinoma cell strain CNE2 xenograft in BALB/c nude mice,while it can not be claimed that Astragalus injection may affect the expression level of p53 mRNA in transplanted tumor tissue.