While our studies are consistent with previous studies demonstrating that colitis in IL10-deficient mice is attenuated under germ-free conditions (Sellon et al., 1998), and that antibiotics can prevent colitis in mice lacking IL10Rβ, or those lacking IL10Rβ and concurrently expressing dnTGFβRII (Kang et al., 2008), the lack of dysbiosis in mice deficient in IL10R suggests that IL10 is not regulating the microbiome per se. This evidence concerns the gene IL10RA and colitis.