I read with extreme interest the article by Zhang et al. (7) about a high prevalence of Campylobacter concisus DNA as well as of immunoglobulin G antibodies to C. concisus in children with Crohn's disease. The role of bacteria in the pathogenesis of inflammatory bowel disease is well recog- nized, but an individual responsible microorganism had not been singled out so far (3). The finding that this particular bacterium, already pinpointed as an emerging pathogen in enteric infections (4), may have a pathogenic role in Crohn's disease provides further evidence of the possible therapeutic role of antibiotics and probiotics for that disorder (3). In this respect, rifaximin, a nonadsorbable antibiotic en- dowed with strong activity against Campylobacter species (2) and devoid of systemic side effects, appears to be a very prom- ising agent. The results of both open-label (6) and double-blind, place- bo-controlled (5) studies have suggested that rifaximin can be effective for active Crohn's disease, although very high doses, up to 1,600 mg daily, may be necessary (5). A case series has recently reported that a short-term rifaximin course followed by long-term administration of probiotics can induce and maintain remission of Crohn's disease (1). Similarly, my coworkers and I observed that in patients intolerant to mesalamine and for whom immunosuppres- sants were not indicated, a 3-month combined therapy with rifaximin at 400 mg in the evening and Saccharomyces bou- lardii at 500 mg in the morning was able to effectively pre- vent clinical relapses (M. Guslandi, A. Cella, and P. A. Testoni, unpublished results). Obviously, further studies are needed to confirm and ex- pand the data from Zhang et al. before it can be claimed that C. concisus represents for Crohn's disease what Helico- bacter pylori (formerly known as Campylobacter pylori, inci- dentally) is for peptic ulcer disease. Nevertheless, I believe that the identification of this new pathogen constitutes an important step in the understanding of the mechanisms in- volved in Crohn's disease and of a more suitable therapeutic approach.