Irritable Bowel Syndrome (IBS) By Stephanie M Moleski, MD, Sidney Kimmel Medical College at Thomas Jefferson University Reviewed / Revised Jul 2022 | Modified Sep 2022 View Patient Education Etiology Symptoms and Signs Diagnosis Treatment Key Points More Information Irritable bowel syndrome is characterized by recurrent abdominal discomfort or pain with at least two of the following characteristics: relation to defecation, association with a change in frequency of stool, or association with a change in consistency of stool.