IL-22 is characterized by numerous clinical relevance to IBD (Fig. 2), including the ability to induce the mucosal healing that represents the current therapeutic goal of IBD, the close involvement in IBD susceptibility gene networks, and the association with CAC, the potential role in an etiological mystery of UC, and the stimulation of expression of a biomarker for IBD. This evidence concerns the gene IL22 and inflammatory bowel disease.