This study was performed to explore the therapeutic effect of Xiezhuo Jiedu Formula on ulcerative colitis rats and its effects on β-catenin/FOSL2/ARID5A signaling pathway and macrophage polarization.Rats of ulcerative colitis was induced and divide into control group,model group,positive group(intervention with sulfasalazine),and low,medium and high-dose groups(intervention with Xiezhuo Jiedu Fang).After 14 days of intervention,the disease activity index(DAI)and colon mucosa damage index(CDMI)were calculated and used to evaluate the state of rats.HE staining was used to observe lesion tissue;ELISA was used to detect of serum levels of TNF-α and IL-6;flow cytometry was used to detect peripheral blood M1 and M2 macrophage content;RT-PCR was used to detect the mRNA expression of iNOS,CD206,and β-Catenin/FOSL2/ARID5A;immunohistochemistry was used to detect β-Catenin/FOSL2/ARID5A signaling pathway protein expression in colon tissue.Data showed that DAI score,CMDI score,and serum TNF-α and IL-6 in the low,medium,and high dose groups were significantly lower than the model group(P＜0.05).HE staining showed that the colon tissue damage and inflammatory infiltration in the low,medium,and high dose groups were slighter than those in the model group(P＜0.05).The rate of M1 type macrophages and iNOS mRNA in the low,medium,and high dose groups were significantly lower than those in the model group,while the rate of M2 type macrophages and CD206 mRNA were significantly higher than those in the model group(P＜0.05).The mRNA and protein expressions of β-catenin and FOSL2 in colon tissue of low,medium,and high dose groups were significantly higher than those of the model group,while the mRNA level and protein expression of ARID5A were significantly lower than that of the model group(P＜0.05).Taken together,Xiezhuo Jiedu formula can effectively alleviate the clinical symptoms,reduce inflammatory response,downregulate β-catenin/FOSL2/ARID5A expression,regulate macrophage polarization and promote disease recovery of ulcerative colitis in rats.