Overview of Irritable Bowel Syndrome

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Irritable bowel syndrome (IBS) is a functional disorder of the colon (large intestine) that causes crampy abdominal pain, bloating, constipation, and/or diarrhea. For this reason, IBS is classified as a functional gastrointestinal disorder because no structural or biochemical cause can be found to explain the symptoms.

Even after diagnostic testing, the colon usually shows no evidence of diseases such as ulcers or inflammation. Therefore, IBS is diagnosed only after all other possible digestive disorders and diseases have been ruled out. Sometimes IBS is misdiagnosed or misnamed as colitis, mucous colitis, spastic colon, inflammatory bowel disease, or spastic bowel (colon). These misnomers persist, even though IBS is now a recognized and treatable condition.

Affecting between 25 and 55 million people in the United States, IBS results in 2.5 to 3.5 million yearly doctors' visits. What's more, 20 to 40 percent of all visits to gastroenterologists are due to IBS symptoms.


When it comes to IBS, there are a number of unpleasant intestinal issues that accompany the issue. While the intensity and severity of symptoms vary from person to person, some of the most predominant symptoms can include:

In some cases, cramps are relieved by a bowel movement; but for some people with IBS, they may have cramps and yet are unable to pass anything. The severity of IBS symptoms varies and could be anywhere from a mild annoyance to debilitating.

Blood in the stool, fever, weight loss, vomiting bile, and persistent pain are not symptoms of IBS and may be the result of some other problem. If you are experiencing any of these symptoms, you need to see a doctor right away.

Additionally, IBS does not lead to any organic disease, such as Crohn’s disease or ulcerative colitis, or any type of bowel cancer. It can, however, increase the likelihood of some mental health issues such as depression and anxiety.


Muscles in the colon normally contract a few times a day, moving feces along and ultimately resulting in a bowel movement. Most doctors agree that in a person with IBS, these muscles are exceptionally sensitive to certain stimuli or triggers. However, researchers are not certain exactly why the muscles are more sensitive.

Although IBS technically is not caused by stress or strong emotions, some people have their first flare-up of IBS symptoms during a stressful period in their life such as the death of a relative or loss of a job. However, these stresses did not cause the condition. Instead, they aggravated it to the point where it became more noticeable or bothersome.

How Diet Affects IBS

Likewise, foods do not cause IBS; but eating certain foods, called "trigger foods" may set off symptoms of diarrhea, bloating, or pain. Some people with IBS also may have food sensitivities. Food sensitivity is a gastrointestinal response to food and different than a true food allergy, which is an immune system response. As a result, food sensitivities may not be detected in traditional allergy tests. Some of the more common causes of food sensitivity include:

  • Sorbitol (a sugar substitute)
  • Fructose (found in fruit juice and dried fruit)
  • Lactose (found in milk)
  • Wheat bran

The best way to identify food sensitivities is by keeping a food and symptom diary.

With the help of your physician, you can trace foods that lead to IBS attacks. The food diary should include not only time and foods eaten, but also where they were eaten, and frame of mind or mood. It is important to include every food and how it was prepared.

The diary should be filled out several times a day so nothing is forgotten. After several weeks, a physician or dietician can review the diary to find trigger food patterns.


IBS is a diagnosis of exclusion, which means that other diseases and infections must be ruled out before it can be diagnosed. For this reason, in 1988 a group of physicians defined criteria to help doctors more accurately diagnose IBS. Known as the Rome Criteria, this set of guidelines outlines symptoms and applies parameters such as frequency and duration.

For instance, the Rome Criteria requires that you have symptoms for at least one day a week in the last three months. It also stipulates that symptoms should have started at least six months prior to your visit. By using the Rome Criteria, doctors can now make a more accurate diagnosis of IBS.

In addition to using the Rome Criteria, physicians often run several tests to ensure that there is no inflammation, infection, or other disease causing the symptoms.

These tests typically include blood tests and fecal occult tests. Other possible testing may include stool cultures, barium enemas, a sigmoidoscopy, and a colonoscopy.

After everything else is ruled out and IBS is diagnosed, patients are typically diagnosed with one of three different types of IBS. These include diarrhea-predominant (D-IBS), constipation-predominant (C-IBS), and alternating constipation and diarrhea (A-IBS).


When it comes to treating IBS, there are several different types of drugs that may be prescribed by a physician. Typically, the goal is to lessen troublesome IBS symptoms such as diarrhea, cramping, pain, or constipation.

The first class of drugs are anticholinergics. These drugs affect the nerve cells or nerve fibers and are used to calm muscle spasms in the intestine and help control symptoms of IBS such as cramping pain or diarrhea. They include dicyclomine, belladonna/phenobarbital, hyoscyamine, and chlordiazepoxide/clidinium.

Meanwhile, antidiarrheals are used to slow down the effect of the bowel and to prevent diarrhea that occurs with IBS. The drugs in this class include diphenoxylate/atropine and alosetron hydrochloride.

For people who want to augment or replace traditional medical therapy, there are some supplements that may help with IBS symptoms. Yet, it is important to note that they also may have side effects; and their use should always be reported to physicians like any prescription drug. Some popular supplements to treat IBS include acidophilus, chamomile, ginger, and peppermint oil.

Finally, some people with IBS complement their medical plan with alternative therapies. Two of the most popular are cognitive behavior therapy (CBT) and hypnosis.

For instance, a ground-breaking study in 1984 showed that IBS patients treated with hypnotherapy demonstrated not only significant improvement in their symptoms but also did not suffer relapses during the three-month study period. As a result, Gut Directed Hypnotherapy was developed specifically for IBS patients and has been proven to reduce symptoms in 80 percent of cases. Meanwhile, CBT helps redefine the associations between worrisome circumstances and a person’s typical reaction to them.


Aside from the pain and discomfort that IBS causes, living with the symptoms on a day-to-day basis can be challenging at times. For instance, you may experience guilt because you have to frequently cancel social engagements; or you may feel lonely and isolated if you feel tethered to your home due to your bathroom issues. Whatever the challenges you face, it is important to look for ways to address these issues in a healthy way.

For this reason, a number of people with IBS look for ways to control the stress in their lives as well as avoid any trigger foods. As a result, they may practice yoga, meditate, exercise, and eat a diet free from trigger foods. Unfortunately, there is no one diet that will work for all people with IBS; but there are some guidelines that may help. For instance, eating several smaller meals during the day, rather than three large ones may help to reduce symptoms, since large meals may result in cramping and diarrhea. A low fat, high protein diet also may help with pain experienced after eating.

By incorporating some of these things into their lives, people with IBS are often able to live a happy and productive life in spite of their condition.

A Word From Verywell

When it comes to IBS, the best way to deal with the condition is to learn as much about it as you can. You also should work to foster a partnership with your doctor. Regular communication about what you are experiencing as well as what works and what doesn't work, will go a long way in improving your situation. Not only will you operate from a position of knowledge, but you also will be able to advocate for yourself and ensure you are getting the best possible care.

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