Accumulating evidence suggests that the gut microbiota plays an important role in the pathogenesis of inflammatory bowel disease (IBD). Carnosic acid (CA) is a major antioxidant component of rosemary and sage. Herein, we investigated the protective effects of dietary CA on dextran sodium sulfate (DSS)- induced colitis mouse model with an emphasis on its impact on the composition and metabolic function of gut microbiota. We found that CA effectively attenuated DSS-stimulated colitis in mice, as evidenced by reduced disease activity index (DAI), and systemic and colonic inflammation. Additionally, CA restored microbial diversity and improved the composition of gut microbiota in DSS-treated mice. Moreover, Spearman’s correlation coeffi cient showed a signifi cant correlation between the fecal metabolites and the gut microbiota species. Changes in gut microbiota and the correlated metabolites might partially explain CA’s anti-infl ammatory effects against colitis. Future clinical trials are needed to determine the therapeutic effects and mechanisms of CA on IBD in humans.