Irritable Bowel Syndrome (IBS)

What is irritable bowel syndrome (IBS) ?

Irritable bowel syndrome is a chronic (ongoing) problem with the large intestine. IBS is not one specific disease. It is a term used to describe a group of symptoms that typically happen together.

Irritable bowel syndrome (IBS) is a group of symptoms that affects the organs responsible for digestion (gastrointestinal or GI tract).

Common irritable bowel syndrome symptoms include abdominal pain, bloating, and diarrhea or constipation, or a combination of both diarrhea and constipation. IBS may cause physical discomfort and emotional distress, but it does not cause damage to the large intestine.

It’s not the same as inflammatory bowel diseases like ulcerative colitis, which do damage the intestine.

IBS is very common and occurs more often in women. Irritable bowel syndrome also has been called functional bowel syndrome, irritable colon, spastic bowel, and spastic colon.

To regulate how the GI tract works, the body sends signals back and forth between the intestines and the brain. If you have IBS, there may be a problem with these signals.

As a result, the GI tract does not function normally. The intestines may become more sensitive and overreact to certain things. This may be especially true when you eat certain foods or when you are under stress.

There are four types of IBS. These may be determined based on the consistency of your stool (feces):

  • IBS with diarrhea.
  • IBS with constipation.
  • Mixed IBS.
  • Unsubtyped IBS.

It is important to know which type of IBS you have. Certain treatments are more likely to be helpful for certain types of IBS.

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by chronic or recurrent abdominal pain or discomfort, usually in the lower abdomen, that is associated with altered bowel habits (diarrhea, constipation or a combination of diarrhea and constipation). Bloating, distention, and disordered defecation are commonly associated features. IBS is a disorder of bowel function and is characterized by abnormalities in motility, sensation, and perception. The most commonly accepted criteria used to diagnosis IBS is the Rome III Criteria *

* Criterion fulfilled for the last 3 months with symptom onset at least 6 months prior to diagnosis.which is shown below:

  • Rome III Criteria Diagnostic criterion

Recurrent abdominal pain or discomfort 

† Discomfort means an uncomfortable sensation not described as least 3 days/month in the last 3 months associated with two or more of the following:

  • 1. Improvement with defecation
  • 2. Onset associated with a change in frequency of stool
  • 3. Onset associated with a change in form (appearance) of stool


What are the symptoms of Irritable Bowel Syndrome?

Common symptoms of IBS include:

  • Abdominal pain and cramping (this may go away after having a bowel movement)
  • Bloating and gas
  • Constipation
  • Diarrhea
  • Alternating between constipation and diarrhea
  • Feeling a strong urge to have a bowel movement
  • Feeling like you still need to have a bowel movement after you’ve already had one
  • Mucus in the stool
  • Feeling full after eating a small or regular-sized meal.
  • Frequent gas.
  • A feeling of having more stool left after a bowel movement.

Symptoms are different for each person. You may have some or even all of the symptoms listed above. Most people have mild symptoms, but some people have severe symptoms that affect their day-to-day lives.

Symptoms tend to come and go. They may be triggered by stress, mental health conditions, or certain foods.

Causes & Risk Factors

What causes Irritable Bowel Syndrome?

Doctors describe Irritable Bowel Syndrome as a “functional gastrointestinal disorder.” This means that it is caused by changes in how the gastrointestinal (digestive) system works, but no one knows exactly what causes these changes to occur.

Most doctors and researchers believe that Irritable Bowel Syndrome is caused by a combination of health problems. Possible health problems that may cause or worsen Irritable Bowel Syndrome include:

  • Problems with the nerve signals from your brain to your intestine
  • Problems with how your intestines push food through your system
  • Mental health problems, such as depression, anxiety, and panic disorders
  • An infection in your stomach or intestines
  • An overgrowth of bacteria in the intestines
  • Changes in hormone levels or other body chemicals
  • Undiagnosed food sensitivities or allergies

What increases the risk of IBS?

You may have a higher risk for Irritable Bowel Syndrome if you:

  • Are female.
  • Are younger than 40.
  • Have a family history of IBS.
  • Have a mental health condition, such as depression, anxiety, or post-traumatic stress disorder.
  • Have had a bacterial infection of your GI tract.

Diagnosis & Tests

How is IBS diagnosed?

Irritable Bowel Syndrome may be diagnosed based on a physical exam, your medical history, and your symptoms. You may have tests, such as:

  • Blood tests.
  • Stool test.
  • X-rays.
  • CT scan.
  • Colonoscopy. This is a procedure in which your GI tract is viewed with a long, thin, flexible tube.

Your doctor probably will do a physical exam and ask you about your medical history. Before your appointment, keep a record of your symptoms and when they occur.

Share this record with your doctor at your appointment. Depending on your symptoms, your doctor may also need to do some tests, such as a blood test, stool test, X-ray, or colonoscopy, just to make sure that your symptoms aren’t caused by something else.

Treatment of Irritable Bowel Syndrome

What changes can I make at home to help control my symptoms of IBS?

There is no cure for IBS. but treatment can help relieve symptoms. Treatment depends on the type of Irritable Bowel Syndrome you have, and may include:

  • Changes to your diet, such as:
    • Avoiding foods that cause symptoms.
    • Drinking more water.
    • Following a low-FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet for up to 6 weeks, or as told by your health care provider. FODMAPs are sugars that are hard for some people to digest.
    • Eating more fiber.
    • Eating medium-sized meals at the same times every day.
  • Talk therapy or counseling.
  • Working with a diet and nutrition specialist (dietitian) to help create a food plan that is right for you.
  • Managing your stress.

The best way to help control your symptoms is to:

  • Lead a healthy lifestyle:Eat a varied, healthy diet, and drink plenty of water. Try to eat 5 or 6 smaller meals each day, instead of 3 big meals. Exercise regularly and make sure you’re getting enough sleep.
  • Avoid foods that make your symptoms worse:You may notice that your symptoms get worse when you eat certain foods. Foods that may make Irritable Bowel Syndrome symptoms worse include caffeinated beverages (coffee, tea), carbonated beverages, milk products, alcohol, chocolate, certain fruits, and beans or cabbage (which can cause gas). To help you figure out if a certain food bothers you, keep a food journal. Record what you eat and whether you have any Irritable Bowel Syndrome symptoms. If you find a pattern, talk to your doctor about whether you should remove that food from your diet and how to find healthy substitutes.
  • Find ways to handle stress:Your symptoms may get worse when you’re under stress, such as when you travel, attend social events, or change your daily routine, Talk to your family doctor about ways to deal with stress, such as exercise, relaxation training, or meditation. He or she may have some suggestions or may refer you to someone who can give you some ideas. Your doctor may also suggest that you talk to a counselor about things that are bothering you.

Why may fiber be helpful?

Fiber can be helpful because it helps improve how the intestines work. There are 2 types of fiber:

  • Soluble fiber helps both diarrhea and constipation. It dissolves in water and forms a gel-like material. Many foods, such as oat bran, apples, beans, and citrus fruits, contain soluble fiber. Psyllium, a natural vegetable fiber, also is a soluble fiber. You can buy psyllium supplements (some brand names: Fiberall, Metamucil, Perdiem) to drink, and you can add it to other foods.
  • Insoluble fiber helps constipation by moving material more quickly through your digestive system and adding bulk to your stool. Insoluble fiber is in whole grain breads, nuts, seeds, wheat bran, and many vegetables and fruits.

Increase the fiber in your diet slowly. Some people feel bloated and have gas if they increase their fiber intake too quickly. Gas and bloating usually improve as you get used to eating more fiber. The best way to increase your fiber intake is eat a wide variety of high-fiber foods.

Can my doctor prescribe medicine for Irritable Bowel Syndrome?

If your symptoms are severe, your doctor may prescribe medicine to help you manage or lessen your symptoms. For example, if your main symptom is pain, your doctor may prescribe antispasmodic medicines such as hyoscyamine or dicyclomine to reduce cramping.

Heating pads and hot baths can also be comforting. If diarrhea is a frequent problem, medicine such as loperamide (brand name: Imodium) may help. If constipation is a problem, your doctor may prescribe a laxative or a medicine called lubiprostone.

Depending on your symptoms, your doctor may prescribe a tranquilizer or sedative, an antidepressant, or an antibiotic. Your doctor may also recommend a probiotic or fiber supplement.

  • Medicines may include:
    • Fiber supplements, if you have constipation.
    • Medicine to control diarrhea (antidiarrheal medicines).
    • Medicine to help control muscle tightening (spasms) in your GI tract (antispasmodic medicines).
    • Medicines to help with mental health conditions, such as antidepressants or tranquilizers.

Will IBS get worse over time?

No. While irritable bowel syndrome will probably recur throughout your life, it won’t get worse. It doesn’t cause cancer or require surgery, and it won’t shorten your life.

What if irritable bowel syndrome interferes with my daily activities?

Irritable bowel syndrome may have caused you to avoid doing certain things, like going out or going to work or school. While it may take some time for your efforts to pay off, you may find new freedom by following a plan that includes a healthy diet, learning new ways to deal with your stress, and avoiding foods that may make your symptoms worse.

Questions to Ask Your Doctor

  • What is a food diary and how will it help you diagnose irritable bowel syndrome.
  • Is irritable bowel syndrome a sign of another health conditions?
  • Are there lifestyle changes I could make that will help IBS?
  • What medicines are available to treat IBS? Are there side effects?
  • What can I do to ease and cope with stress?
  • What are the possible causes of my IBS?

Follow these instructions at home:

Eating and drinking

  • Eat a healthy diet.
  • Eat medium-sized meals at about the same time every day. Do not eat large meals.
  • Gradually eat more fiber-rich foods. These include whole grains, fruits, and vegetables. This may be especially helpful if you have IBS with constipation.
  • Eat a diet low in FODMAPs.
  • Drink enough fluid to keep your urine pale yellow.
  • Keep a journal of foods that seem to trigger symptoms.
  • Avoid foods and drinks that:
    • Contain added sugar.
    • Make your symptoms worse. Dairy products, caffeinated drinks, and carbonated drinks can make symptoms worse for some people.

General instructions

  • Take over-the-counter and prescription medicines and supplements only as told by your health care provider.
  • Get enough exercise. Do at least 150 minutes of moderate-intensity exercise each week.
  • Manage your stress. Getting enough sleep and exercise can help you manage stress.
  • Keep all follow-up visits as told by your health care provider and therapist. This is important.

Alcohol Use

  • Do not drink alcohol if:
    • Your health care provider tells you not to drink.
    • You are pregnant, may be pregnant, or are planning to become pregnant.
  • If you drink alcohol, limit how much you have:
    • 0–1 drink a day for women.
    • 0–2 drinks a day for men.
  • Be aware of how much alcohol is in your drink. In the U.S., one drink equals one typical bottle of beer (12 oz), one-half glass of wine (5 oz), or one shot of hard liquor (1½ oz).

Contact a health care provider if you have:

  • Constant pain.
  • Weight loss.
  • Difficulty or pain when swallowing.
  • Diarrhea that gets worse.

Get help right away if you have:

  • Severe abdominal pain.
  • Fever.
  • Diarrhea with symptoms of dehydration, such as dizziness or dry mouth.
  • Bright red blood in your stool.
  • Stool that is black and tarry.
  • Abdominal swelling.
  • Vomiting that does not stop.
  • Blood in your vomit.


  • Irritable bowel syndrome (IBS) is not one specific disease. It is a group of symptoms that affects digestion.
  • Your intestines may become more sensitive and overreact to certain things. This may be especially true when you eat certain foods or when you are under stress.
  • There is no cure for IBS, but treatment can help relieve symptoms.

Seek Additional Information

  1. International Foundation for Functional Gastrointestinal Disorders (IFFGD). About Irritable Bowel Syndrome. Accessed 08/16/12
  2. The Merck Manual. Irritable Bowel Syndrome (IBS). Accessed 08/16/12
  3. National Digestive Diseases Information Clearinghouse (NDDIC). Irritable Bowel Syndrome. Accessed 08/16/12

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