¹College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, Henan, PR CHINA DOI : 10.9775/kvfd.2025.34687 The present study aimed to combine Portulaca oleracea L with PD to compose a new formula supplemented PD (SPD), and evaluate its effect on ulcerative colitis (UC). The UC mouse model was obtained by supplementing 3.5% dextran sulfate sodium salt (DSS) orally. Subsequently, the mice were treated with PBS, sulfasalazine, high dose SPD, medium dose SPD or low dose SPD. Morphological analysis, RT-qPCR, ELISA assay, LC-MS/MS analysis and 16s rRNA sequencing were conducted to evaluate the effect of SPD on UC. DSS treatment resulted in the decreased body weight and increased DAI value of the mice, while SPD mitigated the changes of body weight and DAI value induced by UC. SPD attenuated the proinflammatory response induced by UC by down regulating the expression of proinflammatory cytokines, and alleviated the oxidative stress in the gut of the mice with UC by downregulating the MDA level and enhancing the activity of antioxidant enzymes. Additionally, SPD also enhanced the transcription of MUC2 and Occludin which were inhibited by UC. Furthermore, DSS induced the dysbiosis of the colonic microbiota and relative abundance of the Akkermansia at genus level was higher in UC group whereas treatment with high-dose SPD restored its abundance to levels comparable to the control group. SPD demonstrated therapeutic effects on DSS-induced UC of the mice by attenuating the proinflammatory response, enhancing the antioxidant ability and key molecules related with barrier function, and modifying the gut microbiota, thereby providing a potential strategy for the treatment of ulcerative colitis. Keywords : Gut microbiota, Supplemented pulsatilla decoction, Ulcerative colitis, Proinflammatory response