IBS is a chronic gastrointestinal (GI) disorder that causes abdominal pain and changes in bowel  movements without any visible signs of damage or disease in the digestive tract. Symptoms can  include: cramping, bloating, diarrhea or constipation, or both, mucus in stool, and the feeling of  incomplete evacuation. Symptoms can be triggered by emotional stress and/or specific foods. The fear of having an IBS episode can sometimes lead to anticipatory anxiety and phobic  avoidance of situations.