Irritable Bowel Syndrome is a group of symptoms – including pain or discomfort in the abdomen and changes in bowel movement patterns – that occur together. It is referred to as a ‘functional gastrointestinal disorder,’ because abnormalities in the gastrointestinal tract are experienced without evidence of damage due to a disease. There are four subtypes of IBS: with diarrhea, with constipation, mixed and unknown.

In the U.S., the prevalence of all types of irritable bowel syndrome is estimated to be 14 percent of the general population. Women are approximately two times as likely to suffer from IBS compared to men, and adults under the age of 45 years are more likely than older adults to be affected.

A 2013 systematic review suggests that the U.S. direct and indirect costs of IBS may be as high as $380 billion.