 NOD-2CARD-15 is a gene that identifies colonic bacteria and can activate the NF-kb pathway in order to destroy the invading bacteria. The identification that mutation of the NOD-2CARD-15 gene increases a persons susceptibility to developing CD suggests that a defect in the innate immunity may impact on the development of the chronic intestinal inflammation. CD patients are also more likely to have an increase in the mucosal permeability, thus allowing colonic bacteria to cross into the mucosal layer. A central role for the colonic bacteria would thus appear to be possible in the development and maintenance of intestinal inflammation and thus the potential effects and benefits of probiotics in the management of CD requires further investigation. 