Excess alcohol consumption and stress are suggested to be key elements in the development of gastrointestinal disorders (Konturek et al., 2011). Dysfunction of the small intestinal barrier function with increased permeability is a common clinical observation in patients with inflammatory bowel syndrome (IBS) and alcoholic liver disease (Sommansson et al., 2013b). Therapeutic administration of the night hormone melatonin have shown to be beneficial and clinical studies have demonstrated attenuated abdominal pain in IBS (Song et al., 2005). This article is protected by copyright. All rights reserved.