 Advancing knowledge regarding the biology of Crohns Disease CD has identified that the hosts innate immunity may impact on the development of intestinal inflammation. Pattern recognition receptors and the Toll-like receptors are able to detect both gram positive and gram negative bacteria, yeasts and flagellin and respond by activation of the innate immune system. By identification of the unmethylated CpG dinucleotide sequences found in bacteria, lymphocytes are stimulated, proinflammatory cytokines like interleukin IL-12 and the interferons are induced, and both the mucosal and host defences against the invading pathogens are increased. 