Irritable Bowel Syndrome (IBS) is a common functional disorder of the large intestine characterized by long-term changes in bowel habits (e.g., frequent diarrhea or constipation) and abdominal pain. The exact causes are unknown, but research suggests that multiple factors — such as the gut-brain axis, abnormal muscular contractions, and gut microbes — could play a role in the disease. IBS can be managed with dietary modifications, psychotherapy, supplements, and prescription medications.