Objective To observe the therapeutic effect of Sanzi Yangqing Decoction （Decoction of three kinds of seeds） for mammary cystic hyperplasia.Methods Totally 113 patients with mammary cystic hyperplastia were randomized into a treatment group （58 cases） which was prescribed Sanzi Yangqing Decoction and a control group （55 cases） which was given Ruhe Sanjie Tablet （Tablet for dissolving mammary masses）. Both were treated for 3 courses. Before and after treatment the clinical symptoms and signs

hormones in serum of both groups

and the indices of hemodynamics of the treatment group were observed.Results The total effective rate of the treatment group was 89.66%

while that of the control group was 65.45%

there was significant difference （P<0.01） between groups. After treatment symptoms and signs in the treatment group were significantly relieved （P<0.01）. Mammary pain and masses and gland edema in the control group were relieved after treatment （P<0.05）. Mammary masses

gland edema and nipple discharge in the treatment group were more significantly relieved than those in the control group （P<0.05 or P<0.01）. Indices of hormones in serum in the treatment group and estradiol in the control group after treatment were significantly improved compared with before treatment （P<0.05 or P<0.01）. Hemodynamics indices of the treatment group were significantly improved （P<0.05）.Conclusion Sanzi Yangqing Decoction is effective for mammary cystic hyperplasia.