Irritable bowel syndrome (IBS) is a common disorder that affects the large intestine. Signs and symptoms include cramping, abdominal pain, bloating, gas, and diarrhea or constipation, or both. IBS is a chronic condition that you'll need to manage long term. Only a small number of people with IBS have severe signs and symptoms. Some people can control their symptoms by managing diet, lifestyle and stress. More-severe symptoms can be treated with medication and counseling The signs and symptoms of IBS vary. The most common include: Abdominal pain, cramping or bloating that is typically relieved or partially relieved by passing a bowel movementExcess gasDiarrhea or constipation — sometimes alternating bouts of diarrhea and constipationMucus in the stool Most people with IBS experience times when the signs and symptoms are worse and times when they improve or even disappear completely.