IBS is a functional disorder of the gastrointestinal (GI) system. In IBS, there is no damage or visible sign of disease in the large intestine, but it does not work properly. IBS can cause diarrhea, constipation, or a mixture of both, along with abdominal pain, bloating, heartburn, and other symptoms. IBS can significantly impact quality of life, negatively affecting work, relationships, social life, and travel.

What Is IBS?

The cause of irritable bowel syndrome is unknown, although researchers have identified many risk factors associated with developing IBS. Some doctors consider functional GI disorders to be caused by communication problems between the gut and the brain.

There are three types of irritable bowel syndrome. IBS-C mainly involves constipation; IBS-D involves mainly diarrhea; and IBS-M involves constipation on some days and diarrhea on other days.

The History of IBS

The first medical case describing irritable bowel syndrome was recorded in 1820 in the United Kingdom. Early case studies noted bloating, abdominal pain, and irregular stools. The term "irritable bowel syndrome" was first used in 1944. Other terms used to refer to IBS over time have included irritable colon, spastic colon, nervous colon, colitis, mucous colitis, and spastic bowel.

In 1978, physician A.P. Manning of Duke University established the Manning criteria for IBS diagnosis. The Manning criteria are based on abdominal pain and loose stools. The Rome III criteria, written in 2006, describes types of IBS according to bowel habit. Both sets of criteria are still used today.

How Common Is IBS?

An estimated 12 to 15 percent of the United States population has IBS. IBS is one of the most commonly diagnosed gastrointestinal conditions in the U.S. Women are about twice as likely to develop IBS as men. Most people who develop IBS are under the age of 50.

Condition Guide

• IBS – The Path to Diagnosis
• Symptoms of Irritable Bowel Syndrome
• Treatments for Irritable Bowel Syndrome (IBS)
• Types of Irritable Bowel Syndrome
• What Causes IBS?