Objective:This study was conducted to evaluate the treatment effectiveness of Chinese herbal medicine capsules containing the Yangyin Shugan formula (YYSG) in premature ovarian insufficiency (POI).Methods:One-hundred forty-six women with POI participated in this stratified, randomized, double-blind, placebo-controlled clinical trial. Participants in two groups (n=73 in each)the YYSG group and control groupunderwent treatment for 12 weeks. Outcome measures included the Chinese version Menopause-Specific Quality of Life questionnaire (CMS), serum levels of basal follicle-stimulating hormone (bFSH), basal estradiol, and anti-Mullerian hormone (AMH), the antral follicle count (AFC), and ovarian peak systolic velocity (PSV; cm/s).Results:Treatment with YYSG significantly reduced the total scores of the CMS at the end of the 12th week with statistical significance (P<0.01); the vasomotor, psychosocial, physical, and sexual domains significantly improvement after treatment (P<0.01). Compared with the baseline hormone levels, YYSG markedly decreased the bFSH level with statistical significance (P<0.01) and improved the AMH level (P<0.01). Furthermore, YYSG greatly improved the participants' AFC and ovarian PSV, compared with placebo (P<0.01). There were no serious adverse events, and the safety indices of whole blood counts, renal function, and liver function were within the normal range, both before and after treatment.Conclusions:Treatment with YYSG was more effective than placebo for improving menopausal symptoms, basal hormone levels, and ovarian function in women with POI in Guangdong, China.