Objective:To investigate the inhibitory effect and mechanism of Danzhi Xiaoyao San(DZXYS) on human breast cancer cell line MCF-7 in nude mice. Method:MCF-7 cells were inoculated in nude mice armpit to establish the subcutaneous tumor model. Female mice were divided to four groups randomly:model group

high-dose DZXYS group (17.98 g·kg-1)

middle-dose DZXYS group (8.99 g·kg-1)

and low-dose DZXYS group (4.50 g·kg-1). Mice of high

middle and low-dose DZXYS groups were orally administrated with DZXYS and model groups with equivalent saline. The treatment course was 15 days. The tumor inhibition rate of tumor mass was observed. Tumor tissue morphology was observed by hematoxylin and eosin(HE) staining. Apoptosis of tumor tissue was observed by Tunel staining. Result:Compared with the model group

DZXYS was statistically significant in middle and high-dose group

and showed a notable tumor mass inhibition effect (P<0.05

P<0.01)

improved tumor morphology

and increase in the number of cells in tumor tissues stained with Tunel and the tumor cell apoptosis rate (P<0.01). Conclusion:DZXYS can inhibit the growth of MCF-7 tumor tissue in nude mice

and its mechanism may be related to promoting tumor cell apoptosis.