Abundant evidence indicates that the intestinal microflora have a role in the pathogenesis of inflammatory bowel disease (IBD). The composition of the gut microflora is altered in IBD patients with increased "pathogenic" bacteria and decreased bifidobacteria and lactobacilli. In light of this dysbiosis, various methods have been examined to alter the composition of the intestinal microflora, including the administration of antibiotics and introduction of probiotic species. This article summarizes studies evaluating the efficacy of antibiotics and probiotics in the induction and maintenance of remission of ulcerative colitis, Crohn's disease, and pouchitis.