 Rationale: IBS is the most common functional gastrointestinal disorder with a prevalence worldwide ranging from 9-23. Complaints include abdominal discomfort or pain and altered bowel habits. Although the condition is not life-threatening, it strongly impairs quality of life and up to now there is no cure for IBS. It is assumed that IBS symptoms are related to a combination of altered gut motility and secretion, and visceral hypersensitivity. However, its primary cause still remains largely unknown. The endocannabinoid system, together with some functionally related receptors is among the biological targets considered promising for treatment. Modulation of the CB1 , CB2 and related receptors or enzymes of the endocannabinoid system in a broader sense by endo cannabinoids or and structurally related lipid mediators can influence motility, secretions and decrease hypersensitivity in the gut. Among the plant-derived cannabinoids or so called phytocannabinoids, cannabidiol CBD is of special interest as it has shown therapeutic potential in preclinical studies and a growing number of case-reports. CBD is a non-specific phytocannabinoid displaying a broad but weak receptor interaction profile. In contrast to the well-known THC from Cannabis sativa, CBD is not psychoactive and often also present in those Cannabis varieties that are not used for their psychoactive properties but for industrial fibre or food properties oil, flour and seeds instead. Based on preclinical studies and in vitro data we hypothesize that CBD might be able to relieve symptoms of IBS, including pain in patients with IBS. The chewing gum is to be taken on demand and may have some additional perceived positive effects. 