Objective: To study the influence of Guizhi Fuling pills (GFP) on pain and matrix metalloproteinases expression in rats with endometriosis. Method: Rat model of endometriosis (EMS) was established. The model rats were divided into the model group

ibuprofen group (0.054 g·kg-1)

danazol group (0.036 g·kg-1)

and GFP low

high dose groups (0.256

1.024 g·kg-1). The treatment in each group was lasted for 4 weeks. Plasma 6-ketone prostaglandin F1α (6-keto-PGF1α)

beta endorphins (beta EP) and thromboxane B2 (TXB2) were determined by radioimmunoassay. Tissue of uterus endometriosis was obtained

and lesions and size were evaluated. The expression of matrix metalloproteinases-2 (MMP-2) and matrix metalloproteinases-9 (MMP-9) in ectopic endometrium was determined. Result: GFP could reduce the volume of ectopic endometrium significantly (P<0.01). Two doses of GFP could increase plasma 6-keto-PGF1α

beta EP level

and reduce TXB2 level (P<0.01). Two doses of GFP could reduce the expression of MMP-2 and MMP-9 (P<0.05

P<0.01). Conclusion: GFP inhibits the growth of ectopic endometrium. The mechanism may be related to inhibition of the expression of MMP-2 and MMP-9.The pain relieving of GFP may be obtained through the balance prostaglandin level

alleviation of spasms of smooth muscle

and elevation of endorphins.