This study investigates the efficacy of a novel sequential laxative-probiotic treatment for Irritable Bowel Syndrome (IBS), guided by mathematical modeling of the gut microbiome. A new non-extinction and defecation-normalized (NEDN) model was developed to simulate the gut microbiome's dynamics. In silico simulations suggested that laxatives create favorable conditions for probiotic intervention. A clinical trial comparing three *Clostridium butyricum* (CB) regimens (laxative followed by CB, laxative with a 2-week interval before CB, and CB alone) showed that the sequential laxative-CB regimen optimally relieved IBS symptoms and improved the gut microbiome composition towards a healthier state. These results highlight the potential of integrating mathematical modeling and clinical trials to optimize microbiome-targeted therapies for IBS.

Ming Li, Ri Xu, Yan-qing Li