Prebiotics and probiotics are focusing increasing interest as treatments for IBD. Currently, there is evidence to support the use of certain probiotics in addition to standard treatments in people with ulcerative colitis but there is no sufficient data to recommend probiotics in people suffering Crohn's disease. Further research is required to identify specific probiotic strains or their combinations and prebiotic substances for therapies of intestinal inflammation. Currently, the probiotic strain, frequency, dose and duration of the probiotic therapy are not established. In severely ill people with IBD there is a risk of the passage of viable bacteria from the gastrointestinal tract to the internal organs (bacterial translocation) and subsequent bacteremia, which can cause serious adverse health consequences. Live bacteria might not be essential because of beneficial effects of probiotics seems to be mediated by their DNA and by secreted soluble factors, and their therapeutic effects may be obtained by systemic administration rather than oral administration.