Since IL10−/− mice have well-characterized time courses of T cell-mediated chronic colitis that is dependent on resident microbiota [21], the goal of our study is to assess the variable effects of CMC or P80 administration on humanized ex-GF IL10−/− mice colonized with pooled feces from patients with active Crohn’s disease and ulcerative colitis. This evidence concerns the gene IL10 and Crohn disease.