By Constance Sommer, AARP Jan 2022 Abdominal pain, bloating and a change in bowel habits warrant a call to your doctor. People with irritable bowel syndrome, or IBS, have a gut that won’t behave, even when it seems like there’s nothing wrong. The intestinal tract of someone with IBS looks healthy in a colonoscopy, and tests that would flag cancer or an autoimmune disorder come back normal — yet the millions of U.S. adults who battle the digestive disorder feel anything but. C