Objective To observe the therapeutic effect of Qingxiang Concentrated Pill (QCP) on mammary gland hyperplasia (MGH) in rats. Methods Injection of estradiol were given to establish rat models of MGH and QCP was given QCP at the same time. Pathologic changes of mammary gland in rats were observed under light microscope. Changes of breast diameter, mammary gland volume and weight were measured; serum sex hormones levels, SOD activity and MDA content were also estimated. Results QCP could decrease the increased breast diameter, mammary gland volume and weight, reduce the numbers of mammary gland lobules and mammary acini and the diameter of acinar cavities. It could also decrease eatradiol level and MDA content in serum, inhibit the decrease of the coefficient of thymus and increase the serum progesterone level. Conclusion QCP can regulate sex hormone levels, inhibit lipid peroxidation and relieve the pathologic changes of mammary gland in MGH rats.