Irritable bowel syndrome (IBS) is a disorder of the large intestine that is characterized by abdominal pain, bloating, cramping and diarrhea or constipation that has lasted at least 6 months. Women are twice as likely as men to develop IBS and it is more common in people who are in their mid-forties or younger. IBS is chronic disorder, meaning it can last for many years, but it is not a disease. Symptoms may come and go over time,