Irritable bowel syndrome (IBS) is a disorder that affects your lower GI (gastrointestinal). This includes the small intestine, large intestine, and colon. It is diagnosed when a person has belly pain or spasm associated with a change in the appearance or frequency of their bowel movements. It causes:

  • Belly cramps
  • Gas
  • Swelling or bloating
  • Changes in your bowel habits, such as diarrhea or constipation

When you have IBS, your colon looks normal. But it does not work the way it should.

Health experts have not been able to find an exact physical cause for IBS. It is often thought that stress is one cause. Stress may make IBS symptoms worse.

IBS is a long-term, chronic condition. It can be painful. But it doesn’t cause lasting harm to your intestines. And it doesn’t lead to serious disease such as cancer.

There is no link between IBS and Crohn's disease, ulcerative colitis, or other inflammatory bowel diseases. However, people with inflammatory bowel disease can also have IBS.


Each person’s symptoms may vary. Some of the most common symptoms include:

  • Having belly pain
  • Having painful constipation or diarrhea
  • Going back and forth between having constipation and having diarrhea
  • Having mucus in your stool

The symptoms of IBS may look like other health problems. Always see your healthcare provider to be sure.

When to Call Your Doctor

Call your healthcare provider right away if your symptoms get worse or if you have new symptoms.