AIM:To investigate the effects of Panax notoginseng compound formula(PN)on endometrial fibro-sis by regulating inflammatory reaction and intestinal flora(IF)in a rat model of intrauterine adhesion(IUA).METHODS:The rat IUA model was established by following the mechanical injury method.A total of 50 rats were randomly divided in-to sham group,model group,low-dose(210 mg/kg)PN group,medium-dose(420 mg/kg)PN group and high-dose(840 mg/kg)PN group.After 8 weeks of intragastric administration,the uterus was collected to observe morphological changes with naked eye.The degree of uterine tissue damage and fibrosis was evaluated through hematoxylin-eosin(HE)and Mas-son staining.The collagen type Ⅰ(Col Ⅰ)was detected by immunohistochemistry.The interleukin-6(IL-6)and IL-10 pro-tein expression was detected by Western blot.The levels of IL-6,IL-1β,tumor necrosis factor-α(TNF-α)and vascular endothelial growth factor B(VEGFB)were detected by enzyme-linked immunosorbent assay(ELISA).The IF diversity and population structure were observed by 16S amplicon.RESULTS:Compared with the sham group,the uteruses of rats in the model group showed:reduced elasticity,accompanied by congestion and edema;decreased number of glands and blood vessels,and thinned endometrium(P<0.01);increased collagen fibers and Col Ⅰ protein expression(P<0.01);sig-nificantly increased IL-1β,IL-6,TNF-α and VEGFB levels in the uterine tissue(P<0.01);decreased IL-10 level(P<0.01);and reduced IF diversity(P<0.05).Compared with the model group,the drug intervention groups exhibited:re-covered elasticity of the uterus and relieved congestion and edema;increased number of endometrial glands and blood ves-sels(P<0.05);decreased collagen fibers and Col Ⅰ protein expression(P<0.01);reduced IL-1β,IL-6,and TNF-α lev-els to varying degrees in the uterine tissue(P<0.05);elevated IL-10 level(P<0.01);and improved IF diversity(P<0.05).CONCLUSION:The PN is able to significantly improve the endometrial tissue fibrosis in IUA rats.The under-lying mechanisms may be related to the inhibition of IL-6,IL-1β and TNF-α expression,up-regulation of IL-10,and im-provement of IF diversity.