Abstract:Objective: To observe the therapeutic effect of Rukuaixiao decoction (RKX) on hyperplasia of mammary gland in rats. Method: 60 SD female rats were radomly divided into blank control group, model group, tamoxifen group and different dose of RKX groups. Injection of estradiol and progesterone were given to establish rat models of mammary gland hyperplasia and RKX was given at the same time. Changes of breast diameter, mammilla height were measured; serum sex hormones levels, blood rheology, SOD activity and MDA content were estimated. Pathologic changes of mammary gland in rats were also observed under light microscope. Result: RKX could decrease the increased breast diameter, mammilla height, reduce the numbers of mammary gland lobules and relieve the pathologic changes of mammary gland. It could also decrease estradiol, prolactin levels and MDA content in serum, increase the serum progesterone level and inhibit the decrease of the coefficient of thymus. Conclusion: Rukuaixiao decoction has the function of treatment on hyperplasia of mammary gland.