Transforming growth factor beta is the protein playing a principal role in the intercellular signalling. The most important functions are: control of cellular growth, differentiation and migration. Moreover it stimulates synthesis of extracellular matrix proteins, modulates immune response and is responsible for angiogenesis, wound formation and tissue reconstruction. All these activities are involved in the development or healing of inflammatory bowel diseases. The role of transforming growth factors beta in the pathogenesis of ulcerative colitis are discussed in this paper.