In a recent study, SMOX deficiency in mice worsened DSS-induced colitis and AOM/DSS-induced colonic tumorigenesis, increased alpha-defensin expression, and induced dysbiosis of gut microbiota, leading to reduced abundance of Prevotella and increased Proteobacteria and Deferribacteres. In contrast, spermidine supplementation reversed the above phenotype. Here, SMOX is linked to colitis.