Although increased intestinal permeability has been reported in intestinal diseases such as IBD,12 probably the best evidence that gut permeability can be directly implicated in the pathogenesis of intestinal disease has been described by Arrieta et al.1 They showed that interleukin 10 (IL-10)–deficient 129(B6)-Il10tm1Cgn mice developed increased small intestinal permeability prior to developing spontaneous colitis. Here, IL10 is linked to colitis.