The global incident shows that the number of inflammatory bowel disease (IBD) cases increased by 88.30% in 2021 and significantly influenced patients' quality of life. Synbiotics are recommended as an alternative or supplement for IBD. We formulated synbiotic mulberry (SM) by mixing mulberry powder, probiotic biomass, and inulin. However, the anti-inflammatory effect of SM and gut microbiota modulation in dextran-sodium-sulfate (DSS)-induced colitis rats has not been thoroughly investigated. Thus, the anti-inflammatory activity of SM and gut microbiota composition was explored using DSS-induced acute colitis rats. Rats were divided into seven groups: control, control+SM1000, DSS, DSS+SM250, DSS+SM500, DSS+SM1000, and DSS+Sulfazalazine (SUL). All DSS induction rats received dissolving 4% (w/v) DSS in drinking water for 7 days, and their respective treatment was once daily via oral gavage. In addition, DSS-aggravated colitis rats received 0.4% (w/v) DSS in drinking water and their respective treatments once daily for the next 7 days. SM improved the disease activity index (DAI), body weight (BW), hepatosplenomegaly, colon length, and colon histomorphology, with outcomes similar to the results of SUL administration. Furthermore, SM decreased the levels of IL-6 production and suppressed iNOS and IL-10 mRNA expression in the colon. SM induced significant modulation in gut microbiota by significantly increasing the abundance of Allobaculu. SM also affects the amount of metabolic enzyme classes. In conclusion, we propose that SM may hold promise as a functional food therapeutic approach for the treatment of colitis; however, additional clinical trials are considered necessary to confirm these effects.