Probiotic research and clinical trials have been forging ahead over the last decade. Although much has been learnt in relation to probiotic intestinal epithelial-mucosal immune interactions, the evidence for substantial clinical efficacy of probiotics continues to progress much slower. This review outlines the probiotic clinical studies before 2005 that formed the foundation of probiotic clinical trials in inflammatory bowel disease and then examines indepth those inflammatory bowel disease probiotic clinical trials published after 2005 that are leading to new understanding of the role of probiotics in the induction and remission of inflammatory bowel disease in humans.