UNLABELLED: Inflammatory bowel disease (IBD) is a chronic gastrointestinal condition with increasing global prevalence. Current therapies are limited, leading to exploration of novel treatments like Pu-erh tea, a fermented tea recognized for its health benefits. This study shows that long-term consumption of Pu-erh tea significantly reduces IBD symptoms in DSS-induced mice by moderating inflammation and enhancing oxidative responses in the colon. Pu-erh tea notably increases the abundance of specific gut microbiota, particularly enhancing Firmicutes, Bacteroidota, and Proteobacteria phyla, and raising levels of Lactobacillus and Muribaculaceae genera. Key species such as Lactobacillus johnsonii, Lactobacillus reuteri, and Lactobacillus murinus also showed increased abundance. Additionally, Pu-erh tea helps restore the integrity of the intestinal barrier. These findings highlight the potential of Pu-erh tea as a complementary dietary strategy for IBD, potentially improving disease management and patient outcomes through its effects on the intestinal microbiota and mucosal barrier. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-024-01696-9.