Irritable bowel syndrome (IBS) is chronic digestive condition. Common symptoms include:

  • cramping
  • abdominal pain
  • bloating
  • gas
  • diarrhea
  • constipation

IBS is different from other bowel disorders, such as Crohn’s disease or ulcerative colitis, because it does not change any of the bowel tissue.

An estimated 10 to 15 percent of adults experience IBS at some point in their lives, but only half of those are diagnosed.

Being aware of the causes and risk factors for IBS may help you reduce the frequency of outbreaks and take steps toward prevention.

Causes of IBS

Doctors still don’t fully understand what causes IBS. Most believe it’s the result of a combination of physical and mental health factors. Some issues believed to cause an IBS flare-up include the following.

Brain-Gut Signal Problems

Messages from the brain to the intestines that aren’t sent or received properly could cause the intestines to work improperly during the digestive process. This may result in IBS symptoms.

GI Motor Issues

The colon’s ability to move during digestion may be too slow — causing constipation — or too fast — causing diarrhea.


Someone with a lower pain threshold may feel the pain of bloating or cramping more than someone with a higher pain threshold.

Mental Health Problems

Stress can often aggravate physical ailments and IBS is no exception. Many doctors suspect a link between panic attacks or depression and IBS. However, whether mental health causes physical symptoms or simply exacerbates them is not known.

Bacterial Gastroenteritis

A bacterial infection within the intestines may lead to IBS symptoms.

Small Intestinal Bacterial Change

A change in the types of bacteria within the small intestine has been shown in some studies to cause excess flatulence and diarrhea.


Many women typically experience worsened IBS symptoms during their menstrual period. This leads some experts to believe there’s a connection between reproductive hormones and bowel problems. This theory is supported by evidence that many women also experience fewer IBS symptoms after menopause.


It’s possible that IBS runs in families. However, whether this is due to a genetic link or to shared environmental factors remains unclear.

Food Sensitivity

Perhaps the most widely known IBS trigger is sensitivity to certain foods. Just as some people find that migraines tend to occur after eating particular foods, some people find that their intestinal distress increases with certain food intake.

Common problem-causing foods include:

  • coffee
  • alcohol
  • spicy foods
  • dairy products
  • overly fatty foods
  • carbohydrates

It’s thought that the intestines may be unable to properly absorb certain components of these foods.

Risk Factors

Certain demographics have been found to be more susceptible to IBS symptoms, including:

  • people who are less than 45 years old
  • women
  • people with a family history of IBS


Researchers are still trying to figure out what exactly causes IBS. The condition is chronic, but lifestyle and diet changes as well as certain prescription medications can help you manage your symptoms.

Talk to your doctor if you’re having any IBS symptoms. They may be related to IBS, but it’s important to make sure they’re not related to a more serious condition. You should learn as much about IBS as you can if you’ve been diagnosed with it. Being knowledgeable about your condition will help you make better decisions for your care.