Objective:To investigate the anti-tumor effect of Shu-Gan-Liang-Xue（SGLX） decoction from traditional Chinese midicine（TCM） combined with tamoxifen on the graft model of human breast cancer in nude mice and also to analyze the possible mechanism.Methods:The animal model of MCF-7 implanted tumor in nude mice was copied.Mice with implanted tumor were randomly divided into control

tamoxifen（TAM）

SGLX and SGLX+TAM groups.After SGLX decoction was given to mice for 28 days

the inhibitory rate of tumor weight was determined.Cell cycle and cell apoptosis of breast cancer were detected with flow cytometry and TUNEL respectively.The serum estradiol and progesterone were tested by radio-immunity.Results:The inhibitory rate of tumor-weight was 28.30%

26.30%

41.01% respectively in TAM

SGLX and SGLX+TAM groups

with significant difference compared with the control（P

<

0.01）.Tumor cells in TAM

SGLX and SGLX+TAM groups were blocked at G

0

/G

1

phase.The apoptotic rate was increased obviously in SGLX+TAM group.The serum estradiol was lower in SGLX and SGLX+TAM groups compared with the control at significant level（P

<

0.000 1）.Conclusions:SGLX decoction can increase the inhibitory effect of TAM on breast cancer synergetically.The possible mechanism include that SGLX may arrest tumor cells in G

0

/G

1

phase

induce tumor cell apoptosis

and reduce serum estradiol level.