Objective To investigate the therapeutic effects and mechanisms of emodin(EMO)on dextran sulfate(DSS)-induced ulcerative colitis(UC)in mice.Methods DSS induced UC mouse model,detection of body weight,colon length and histopathological changes.Enzyme-linked immunosorbent assay(ELISA)was used to measure tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),interleukin-6(IL-6),interleukin-10(IL-10),and myeloperoxidase(MPO)levels.Western blot analysis examined the expression of Toll-like receptor 4(TLR4)/myeloid differentiation factor 88(MyD88)/nuclear factor κB(NF-κB)signaling pathway-related proteins.Flow cytometry assessed the ratio of helper T cells 17(Th17)to regulatory T cells(Treg).Additionally,16S rDNA sequencing was employed to evaluate gut microbiota composition.Results Compared with the normal group,DSS-treated mice exhibited significant weight loss,shortened colon length,and marked histological damage(P<0.001).EMO intervention,particularly at high doses,demonstrated dose-dependent improvements in body weight and colon injury(P<0.05).ELISA analysis showed EMO reduced TNF-α,IL-1β,and IL-6 levels while increasing IL-10(P<0.05).Western blot results indicated EMO inhibited abnormal activation of the TLR4/MyD88/NF-κB pathway and restored IκB.Conclusion EMO effectively mitigates DSS-induced ulcerative colitis(UC)inflammation and intestinal damage by regulating the TLR4/MyD88/NF-κB pathway,restoring Th17/Treg balance,and maintaining microbial homeostasis,providing theoretical support for its potential as a UC therapeutic agent.