Objective:To explore the effect of Danggui Shaoyao Powder(DGSYP)on the Toll-like receptor 4(TLR4)/Myeloid differen-tiation factor 88(MyD88)/Nuclear factor-κB(NF-κB)signaling pathway in ulcerative colitis(UC)rats.Methods:Forty-eight male SD rats were randomly divided into 6 groups:normal group,model group,DGSYP low-dose group(11.61 g/kg),medium-dose group(23.22 g/kg),high-dose group(46.44 g/kg)and salazosulapyridine group(0.36 g/kg).There were 8 rats in each group.In addition to the normal group,the rats in other groups were induced by 5%sodium trinitrobenzene sulfonate(TNBS)to establish a UC rat model.After successful modeling,each drug treatment group continued to administer the intervention for 14 days.At the same time,the rats in the normal group and the model group were given equal volume of nor-mal saline.The disease activity index(DAI)score was calculated.hematoxylin-eosin(HE)staining was used to observe the histo-pathological changes in the colon of rats.The levels of interleukin-6(IL-6),IL-1β,and tumor necrosis factor α(TNF-α)in colon tissue were measured by enzyme-linked immunosorbent assay(ELISA).Real-time fluorescence quantitative polymerase chain re-action(RT-qPCR)was used to detect the mRNA expression levels of TLR4,MyD88 and NF-κB p65 in colon tissues.The expression levels of TLR4,MyD88 and NF-κB in colon tissues were detected by Western blot(WB).Results:Compared with the normal group,the DAI score of the model group was increased,the colon was shortened,the histopathological changeswere obvious.The levels of in-flammatory factors IL-6,IL-1β and TNF-α in colon tissue of model group were significantly increased(P<0.01),the mRNA and pro-tein expressions of TLR4,MyD88 and NF-κB p65 were also significantly increased(P<0.05,P<0.01).Compared with the model group,the above disease-related conditions of rats in each treatment group of DGSYP were improved to varying degrees,DAI fraction decreased significantly(P<0.05),colon growth,no obvious edema or edema degree decreased,the histopathological changes of colon were improved to varying degrees.The levels of inflammatory factors IL-6,IL-1β and TNF-α in colon tissues were significantly de-creased(P<0.01),and the mRNA and protein expressions of TLR4,MyD88 and NF-κB p65 were significantly decreased(P<0.05,P<0.01).Conclusion:DGSYP can regulate the TLR4/MyD88/NF-κB signaling pathway,thereby reducing the release of inflammatory fac-tors,and then alleviating the degree of inflammatory damage in the colon of UC rats.