Objective To evaluate the efficacy and safety of Tiangui Capsule in treating polycystic ovary syndrome（ PCOS）. Methods Totally 291 cases of PCOS were randomized into Tiangui Capsule group（ 112 cases

treated with Tiangui Capsule）

Glucophage group（ 93 cases

treated with metformin hydrochloride） and diane-35group（ 86 cases

treated with ethinylestradiol and cyproterone acetate tablet）. The treatment of Tiangui Capsule group and Glucophage group lasted for 3 months and diane-35 group was treated for three circles

each circle lasted for 21 days. The anthropometry indexes including height

weight

body mass index（ BMI） and waist-hip ratio（ WHR）

menstrual changes

reproductive hormone level changes such as follicle stimulating hormone（ FSH）

luteinizing hormone（ LH）

estradiol（ E2）

prolactin（ PRL）

testosterone（ T）

dehydroepi and rosterone sulfate（ DHEA-S）

sex hormone binding globulin（ SHBG） and free androgen index（ FAI） and changes of glycometabolism and lipid metabolism including homeostasis model assessment for insulin resistance（ HOMA-IR）

total cholesterol（ TC）

triglyceride（ TG）

high density lipoprotein（ HDL） and low density lipoprotein（ LDL） in all groups were observed after treatment. Results As for improving menstrual condition

the total effective rate of Tiangui Capsule group and Glucophage group was 74. 55% and 69. 84% respectively

with a significant difference between groups（ P <0.05）. After treatment

the body weight in Tiangui Capsule group and Glucophage group was significantly decreased（ P < 0. 01）. Tiangui Capsule could significantly reduce the levels of FSH and T（ P < 0. 01）. After treatment

the levels of LH

T and LH /FSH in diane-35 group were significantly decreased but the level of SHBG was significantly increased（ P < 0. 01）. The level of HOMA-IR in Tiangui Capsule group and Glucophage group was significantly decreased after treatment（ P < 0. 05）. The level of TC in Tiangui Capsule group was significantly decreased（ P <0.05）. The level of TC was significantly decreased but the level of LDL was significantly increased in Glucophage group（ P < 0. 05）. The level of HDL was significantly decreased（ P < 0. 01） but the level of LDL was significantly increased（ P < 0. 01） in diane-35 group. The ovarian volume in Tiangui Capsule group and diane-35 group was significantly reduced after treatment（ P < 0. 01）. There was no remarkable side effect in Tiangui Capsule group

while mild side effect was found in the other two groups. Conclusion Tiangui Capsule can obviously improve menstrual cycle

enhance ovulation rate

reduce body weight and androgen levels

strengthen insulin sensitivity and decrease total cholesterol level without adverse reaction.