Irritable Bowel Syndrome

When functioning properly, the muscles of the digestive tract contract to move food through. Irritable Bowel Syndrome (IBS) occurs when normal digestive tract motility is disrupted, causing uncomfortable symptoms that affect about 1 in 6 Americans.


There are many possible causes of Irritable Bowel Syndrome. For example, there may be a problem with muscles in the intestine, or the intestine may be more sensitive to stretching or movement.

Risk Factors

IBS can occur at any age, but it often begins in adolescence or early adulthood. It is more common in women and is the most common intestinal complaint for which patients are referred to a gastroenterologist. Stress can cause symptoms to worsen.

Common Symptoms of IBS 

  • Abdominal pain, fullness, gas, and bloating present for at least 6 months
  • Intermittent pain that occurs after meals and is relieved by bowel movements
  • Constipation and/or diarrhea
  • Loss of appetite

Diagnostic Tests

Your doctor can often diagnose Irritable Bowel Syndrome based on your symptoms. Eating a lactose-free diet for 2 weeks may help the doctor evaluate for a possible lactase deficiency.

There is no specific test to diagnose IBS, but tests may be done to rule out other problems:

  • Blood tests to see if you have a low blood count (anemia)
  • Stool cultures to rule out an infection
  • Sigmoidoscopy or colonoscopy


The following lifestyle changes can be helpful in some cases of IBS:

  • Regular exercise
  • Improved sleep habits
  • Avoidance of foods and beverages that stimulate the intestines, such as caffeinated drinks
  • Avoidance of large meals and certain foods (wheat, chocolate, dairy products, alcohol, for instance)
  • Increased dietary fiber

No one medication will work for everyone, but your doctor may try:

  • Anticholinergic medications (dicyclomine, propantheline, belladonna and hyoscyamine) taken about a half-hour before eating to control colon muscle spasms
  • Loperamide to treat diarrhea
  • Low doses of tricyclic antidepressants to help relieve intestinal pain
  • Lubiprostone for constipation symptoms
  • Medications that relax muscles in the intestines
  • Counseling may help in cases of severe anxiety or depression.