The aim of the study was to evaluate the role of TGF-β1 in the pathogenesis of inflammatory bowel diseases (IBD) and to assess whether levels of either TGF-β1 and/or mRNA of its gene, in either plasma or tissue expression, can be useful in diagnosing and/or monitoring of the clinical course of these diseases. This evidence concerns the gene TGFB1 and inflammatory bowel disease.