Objective To explore the pathogenesis of liver qi reversion in premenstrual syndrome（PMS）and the intervention mechanism of Jingqianping Granule（Granule for premenstrual disorders）.Methods Thirty non-estrus SD rats were randomized into normal control group

model group

and Jingqianping Granule group

with 10 in each.Except the normal control group

other two groups were made PMS liver qi reversion models with the stimulation from the digital impulse electrical stimulation noise interference apparatus for 5 days.The normal control group and model group were treated with intragastric feeding with normal saline 1ml/100mg body weight

and the Jingqianping Granule group was administered Jingqianping Granule（0.16g/100g body weight）

once a day

5 days in succession.The expression of μ opium receptor mRNA and protein in the hypothalamus and hippocampus of all groups was determined.Results The expression of μ opium receptor mRNA and protein in the hypothalamus and hippocampus of PMS rats with liver qi reversion was all increased significantly

Jingqianping Granule could make it restored to nearly normal level.Conclusion Increase of μ opium receptor in the hypothalamus and hippocampus is one of pathogenic mechanisms of PMS and Jingqianping Granule functions to exert its influence through inhibiting the increase of this receptor.