Objective To research the possible mechanism of Xiaoyao Pill（Free Wanderer Pill）for infertility.Methods Sixty cases of infertility undergoing in vitro fertilization-embryo transfer（IVF-ET）were grouped into the treatment group（21 cases

with liver depression pattern）and control group（39cases）.Both groups were induced ovulation with routine western medicine and the treatment group was added with Xiaoyao Pill orally

20pills once

in the morning and evening.The expressions of activin receptor-like kinase 5（ALK5）

Smad2

Smad3and Smad4proteins

ALK5mRNA

Smad2mRNA

Smad3 mRNA and Smad4mRNA of granulosa cells in wall of ovarian follicle in both groups were detected.Results The expressions of ALK5protein

Smad2protein

ALK5mRNA and Smad2mRNA were significantly higher than those in the control group（P<0.05）.There was no significant difference between groups in the expressions of Smad3protein

Smad4protein

Smad3 mRNA and Smad4mRNA（P>0.05）.Conclusion The possible mechanism of Xiaoyao Pill for infertility is up-regulating the expressions of ALK5protein

Smad2protein

ALK5mRNA and Smad2mRNA and regulating ALK5/Smads signaling pathway to promote the follicular development and regulate ovarian function.