Ulcerative colitis is a chronic inflammatory disease primarily involving the colon. It has long been considered to be due to a dysregulated immune response targeting the colon, and involves unknown environmental factors . Recent studies have highlighted several characteristics which may suggest that UC is associated with alterations of the microbiota, defective production of short chain fatty acids and an impaired mucous layer. However at present, no effective therapy targets the microbiota or its interaction with the colonic epithelium. UC in humans is characterized by increased mucosal sulfides and increased sulfate and sulfide reducing bacteria and activation of amino acid metabolism pathways which impair butyrate production, whereas certain dietary patterns in humans and rodent models may induce dysbiosis and favor sulphide reducing bacteria. Further support for targeting the microbiota includes several studies demonstrating that antibiotics might be helpful for severe refractory colitis. Development of treatment strategies that target the microbiota could reduce exposure to immune suppression, and add new therapeutic strategies that do not exist at present.