Inflammatory bowel disease, such as ulcerative colitis and Crohns disease, results from an interaction between susceptibility genes, the hosts bacterial environment, gut barrier defects, and immunological factors. New management approaches have been evolved from advances in our understanding of the pathobiology of this common gut disorder In particular, the therapeutic manipulation of the bacterial microenvironment in the gut seems to offer an innovative tool for the treatment of those patients. Since the gut is a highly sensitizing organ that contributes to the systemic imune response, potent treatments need to be developed to reduce gut inflammation in this disorder. Recent studies have demonstrated that probiotic lactobacilli, and also immunostimulatory DNA sequences from those same bacteria have an important antiinflammatory potential in this context. Future research should better define among patients with inflammatory bowel disease the various clinical phenotypes with the greatest potential of response to probiotic treatment. Identification of the genes leading to the disease and a rather better understanding of the underlying immunoregulatory abnormalities will be crucial steps to define the different profiles of interaction between endogenous digestive bacterial flora and the immune system in each individual patient. Such advances will probably lead to targeting of effective treatments, including bacteriotherapy with probiotic lactobacilli, to subsets of patients with inflammatory bowel disease.