Live B. coagulans BC198 ameliorated colitis by increasing gut barrier-associated proteinexpression, reducing neutrophil and M1 macrophage infiltration ofcolon tissue, decreasing the Th17/Treg ratio in the spleen, and increasingTreg cells and their anti-inflammatory cytokine, IL-10, in the colon.These beneficial effects may be related to the role of B. coagulans in regulating the gut microbiota, includingincreasing the relative abundance of beneficial commensal speciesthat promote Treg cell accumulation in the colon. Here, IL10 is linked to colitis.