Irritable Bowel Syndrome (IBS) Patient Information Fact Sheet

What is irritable bowel syndrome?
Irritable bowel syndrome (IBS) consists of a number of symptoms. The most important symptoms in IBS are abdominal pain and abnormal bowel habit. Many patients with IBS get crampy abdominal discomfort or pain, which comes and goes, and is often relieved by emptying the bowels. The bowel habit is often irregular—sometimes diarrhea, sometimes constipation and quite often swinging between these two extremes. Some patients may notice they need to get to a bathroom in a hurry. Other symptoms vary from individual to individual but include a sensation of bloating, visible abdominal swelling, a sense of incomplete emptying of the bowels and passage of mucus from the rectum. Many patients notice that they lack energy and sleep poorly.

Is IBS common?
IBS is one of the most common disorders of the digestive system and up to one-third of the population experience symptoms from time to time. Women are slightly more affected than men and IBS is most often found in people under the age of 45. IBS is one of the most common reasons for patients to visit a doctor. In turn it is also a very frequent reason for doctors to refer patients to a specialist in gastrointestinal disorders.

What causes IBS?
It's not thought that IBS has a single cause. There seem to be many reasons why patients develop the condition. In some people, eating irregularly or taking an abnormal diet may be responsible. Others notice IBS developing after they have had a bout of food poisoning or gastroenteritis. Some people believe that stress makes their symptoms worse. It seems probable, however, that there are other causes that are not yet known.

Why is IBS painful?
During digestion, the intestine squeezes its contents along our insides toward the anus for elimination. This process is usually painless and we do not realize that it is happening unless there is abnormal squeeze within the bowel or, for some reason, the intestine becomes overactive. These changes can be quite painful. Some patients with IBS seem to be very sensitive to the way that their intestines are moving.

Are there different types of IBS?
Some IBS patients suffer mostly from constipation, some experience diarrhea, while others have both symptoms at different times. The form of IBS that seems to follow gastroenteritis often leads to persistent diarrhea. Identifying these different types of IBS is important because treatments often work quite differently depending upon whether diarrhea or constipation is the main problem. However, we do know that the pattern of bowel movements can alter over time and this means that your treatment might need to change should your symptoms vary.

Is IBS serious?
Although the symptoms of IBS can be similar to those seen in more serious conditions, once IBS has been diagnosed there is no reason to think that it will develop into anything worse. In particular, patients with IBS are no more likely than anyone else to develop bowel cancer.

What tests confirm a diagnosis of IBS?
Your doctor will want to rule out other diseases, but will probably be able to make a diagnosis based on the symptoms that you describe. On occasion it may be necessary to do simple blood tests to rule out anemia, to make sure the liver and thyroid gland are working properly, and to exclude any evidence of inflammation within the bowel. You might also have a blood test to look for intolerance to wheat (gluten). Furthermore, additional diagnostic tests may include a stool test, lower GI series, flexible sigmoidoscopy or colonoscopy.

When should I see my doctor?
You may have had symptoms for many years without seeking help from your doctor, and this is fine as long as you are coping well. Obviously, your doctor is there to help you if symptoms become troublesome or interfere with your life. If you develop any of the symptoms below, which are not usually associated with IBS but may be associated with other diseases, contact your doctor:

  • A change in bowel habit - especially if you are over the age of 40
  • Passing blood from the rectum
  • Unintentional weight loss of more than 4 pounds
  • Diarrhea waking you from sleep
  • Fever

How is IBS treated?
If a dietary cause is suspected, your doctor may be able to give you some advice on what to eat or may suggest that you see a nutritionist to identify foods that upset you. You may be asked to leave out particular foods from your diet, such as wheat, to see if that helps to alleviate your symptoms. Alternatively, you may be asked to try an “exclusion diet,” which involves excluding from your diet a number of different foods that commonly upset patients with IBS. If your symptoms improve, individual items can then be added back into your diet until the specific food or foods that seem to upset you are identified. If constipation is the main problem, then bulking agents such as natural bran fiber containing cereals, and products containing psyllium (Konsyl), polycarbophil (Fibercon), or methylcellulose (Citrucel) are helpful.

Drugs to reduce bowel spasm have been used for many years to treat IBS. They are generally very safe and often worth trying. Most are available without a prescription and your pharmacist can advise you. Unfortunately, they only benefit a relatively small number of patients. Lubiprostone (Amitiza) is a prescription drug available to treat IBS when constipation is the main symptom. Alosetron (Lotronex) is approved to treat IBS women with diarrhea-predominant IBS when other measures have failed to bring relief.

Self-help measures
A healthy lifestyle may improve symptoms. Pay particular care to your eating habits and develop a regular routine for emptying your bowels. You may find that particular foods trigger an attack of pain. Keeping a food diary together with a record of bowel symptoms may be helpful since you might be able to see whether there is a pattern. Foods that commonly cause upset include wheat products, dairy products, onions, nuts and caffeine-containing drinks such as coffee, tea and cola. Some patients cannot digest lactose (the sugar in milk) and so develop gas and diarrhea after eating large amounts of milk or dairy products.

Further information
National Digestive Diseases Information Clearinghouse (NDDIC):

Last Reviewed: May 2013