Irritable Bowel Syndrome FAQs

IBS Questions & Answers

Irritable bowel syndrome is a chronic condition of the large intestine that causes discomfort and disruption in the lives of those affected. Find out more about this condition and how Mercy gastroenterologists can help.

IBS is a chronic condition that affects your large intestine. It’s characterized by abdominal pain or discomfort caused by changes in your bowel habits ― either diarrhea, constipation or both. IBS is different from occasional constipation or diarrhea, and the symptoms are recurring. It’s a common condition, affecting about twice as many women as men.

The exact cause of IBS isn’t known, but several factors are believed to play a role.


  • Changes in muscle contractions – Muscles contract as food moves through your digestive tract. Stronger and longer-lasting contractions can cause diarrhea, gas and bloating. Weaker contractions may slow digestion, leading to hard, dry stools.
  • Digestive nerve malfunctions – Poor signals between the intestines and brain can cause abnormal responses to the digestive process, resulting in painful bowel movements, diarrhea or constipation.
  • Intestinal inflammation – People with IBS may have more immune-system cells in their intestines, which can lead to pain and diarrhea.
  • Infection – Diarrhea caused by a virus or bacteria can trigger IBS. And the condition may be caused by a surplus of intestinal bacteria (or bacterial overgrowth).
  • Different gut bacteria (microflora) – The "good" bacteria (or microflora) in the intestines may be different in people with IBS compared to healthy people.

Persistent abdominal pain and cramping are the most common IBS symptoms. Other symptoms include changes in bowel habits like diarrhea or constipation, bloating, gas, urgency and loss of appetite.

The exact cause of IBS is unknown. But doctors believe several factors may contribute to it, including nerve and muscle dysfunction, immune response, infection and bacteria overgrowth. While it hasn’t been proven, some experts believe there may be a genetic link.

IBS symptoms usually come and go over time in most people. Severe symptoms may require prescription medication, so be sure to seek treatment from a Mercy provider.

People who have IBS experience symptoms at least three times a month for a minimum of six months. Unfortunately, there isn’t one test to detect IBS. Your Mercy provider or gastroenterologist will likely review your medical history, discuss your symptoms and perform a physical exam to help determine if you have IBS. And you may have other tests to rule out causes for your symptoms, such as an X-ray, CT scan, colonoscopy, endoscopy or stool tests.

In general, avoid foods that cause gas like carbonated beverages and certain vegetables. And some people with IBS seem to improve by eliminating gluten from their diet. A Mercy dietitian can help you with menu planning and tips on eating healthy.