Conditions InDepth: Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome (IBS) is a range of symptoms that happen at the same time. Belly pain, cramping, gas, bloating, and changes in bowel habits are the most common issues. Pain from IBS is often better after a bowel movement.

The Intestines

Copyright © Nucleus Medical Media, Inc.

Causes of IBS

IBS is a functional disorder that affects the intestines. The exact cause is unknown. Nerves, muscles, air, and movement all help the intestines work smoothly. One or more problems in any of these pathways can lead to IBS. Increased sensitivity in your intestines can be influenced by:

  • Infection or inflammation
  • Changes in the normal bacteria of the intestines—may lead to more gas production
  • Certain foods
  • Stress, anxiety, or depression
  • Missing enzymes that breakdown certain sugars—present from birth (rare)

Types of IBS

IBS types are based on the bowel habit that is causing the most problems:



Definition and facts for rritable bowel syndrome. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at: Updated November 2017. Accessed June 7, 2019.
Ford AC, Lacy BE, Talley NJ. Irritable bowel syndrome. N Engl J Med. 2017;376(26):2566-2578.
Irritable bowel syndrome (IBS). EBSCO DynaMed Plus website. Available at: http://www.dynamed.... Updated September 10, 2018. Accessed June 7, 2019.
Wilkins T, Pepitone C, Alex B, Schade RR. Diagnosis and management of IBS in adults. Am Fam Physician. 2012;86(5):419-426.
Last reviewed December 2018 by EBSCO Medical Review Board Daus Mahnke, MD
Last Updated: 6/7/2019

EBSCO Information Services is fully accredited by URAC. URAC is an independent, nonprofit health care accrediting organization dedicated to promoting health care quality through accreditation, certification and commendation.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

To send comments or feedback to our Editorial Team regarding the content please email us at Our Health Library Support team will respond to your email request within 2 business days.