What is the definition of irritable bowel syndrome (IBS)?
Irritable bowel syndrome (IBS) is a gastrointestinal disorder characterized by the presence of a cluster of symptoms and signs in adult or children that include cramping, abdominal pain, increased gas, altered bowel habits, food intolerance, and bloating (distention).
Irritable bowel syndrome is a "functional" disorder. This term refers to the changes in the functioning of the digestive system that results in the collection of symptoms referred to as IBS, meaning that it is a problem with the movement (motility) rather than any damage to the tissues of the digestive system.
In the past, irritable bowel syndrome was also called spastic colon or bowel, functional bowel disease, mucous colitis, or nervous colon. IBS is not the same as colitis, which is a group of separate conditions also referred to as inflammatory bowel disease (IBD).