Irritable Bowel Syndrome (IBS)

What Is It?

Irritable bowel syndrome (IBS) is a common disorder that causes a variety of symptoms, including abdominal pain, diarrhea and/or constipation, bloating, gassiness, and cramping. Because these symptoms may be caused by a number of different bowel diseases, IBS is usually diagnosed only after your doctor determines you don’t have a more serious problem.

The severity of the disorder varies from person to person. Some people experience symptoms that come and go and are just mildly annoying, while others have such severe daily bowel problems that IBS affects their ability to work, sleep, and enjoy life. In addition, symptoms may change over time. A person may have severe symptoms for several weeks and then feel well for months or even years. Most people are never cured of IBS, but the disorder is not related to any other disease and does not develop into any other disease, such as ulcerative colitis or colon cancer.

IBS usually starts in early adulthood. It affects twice as many women as men. Approximately 10% to 20% of the population has IBS, but at least half of all people with the condition never seek medical care for their symptoms. No one knows what causes IBS. Some studies suggest that the nerves of the colon may be much more sensitive than usual in people with IBS. The normal movement of food and gas through the colon causes pain, intestinal spasms, and an irregular pattern of bowel movements.

In the past, it was thought that stress might cause IBS. That is no longer the case. Stress does not cause IBS, but stress can increase the symptoms, especially pain.

IBS has been called irritable colon, spastic colon, mucous colitis, and functional bowel disease.


People with IBS may have some or all of these symptoms:

  • Mild or severe abdominal pain, discomfort or cramping that usually goes away after a bowel movement
  • Periods of diarrhea or constipation, or alternating between these two symptoms
  • Bloating, gassiness, or a feeling of having a distended abdomen
  • Mucus in bowel movements
  • Feeling as though a bowel movement is incomplete
  • In extreme cases, nausea, dizziness or fainting

Although the symptoms of IBS often change over time, people tend to develop their own patterns. For example, some people have mostly diarrhea, some have mostly constipation and others have abdominal pain without a major change in bowel movements.


There is no test for IBS. Your doctor will diagnose IBS if you have the typical symptoms and have been tested for other disorders that can cause similar symptoms. Your doctor will ask about your medical history and symptoms. Your doctor will examine you, testing your abdomen for tenderness and feeling to determine whether internal organs are larger than normal. The doctor will check for fever or weight loss. If you have any of these signs, you may have something other than IBS.

Depending on your medical history, your doctor may do tests to eliminate other diseases that may cause similar symptoms. These tests might include:

  • Blood tests
  • A stool sample, to check for blood or evidence of infection
  • Sigmoidoscopy, in which a flexible, lighted tube with a tiny camera on the end is inserted into the rectum and up the left side of the colon, or a colonoscopy, in which a longer tube examines the entire colon
  • Barium X-ray, in which a chalky solution is swallowed or pumped into the rectum to coat the inside of the gastrointestinal tract and highlight abnormalities
  • Asking you to stop eating or drinking certain foods for up to three weeks to determine if your diet is contributing to your symptoms (for example, your doctor may ask you to eliminate milk products if he or she suspects lactose intolerance)

Expected Duration

IBS symptoms may be a daily problem throughout a person’s life, or symptoms may come and go, lasting a day, a week, or a month before disappearing. Treatment may get rid of symptoms, and dietary changes may help to reduce the frequency or severity of symptoms.


Because no one knows what causes IBS, it is impossible to prevent the disorder. Once diagnosed with IBS, a person may be able to reduce the frequency and severity of symptoms by reducing stress or changing the diet.


One of the most helpful ways to treat IBS is to change your diet. This can minimize symptoms, or it can reduce the likelihood that an IBS attack will occur.

In almost every case, different foods tend to trigger IBS symptoms. Doctors recommend monitoring what you eat so you can find out what you ate before an attack. After you discover your particular trigger foods, eliminate them from your diet. Some common IBS trigger foods include:

  • Cabbage, broccoli, kale, legumes, and other gas-producing foods
  • Caffeine
  • Alcohol
  • Dairy products
  • Fatty foods, including whole milk, cream, cheese, butter, oils, meats, and avocados
  • Raw fruits
  • Foods, gums, and beverages that contain sorbitol, an artificial sweetener

The way you eat may help to create IBS symptoms. Eating large meals can cause cramping and diarrhea, so eating smaller meals more often may help some people with IBS. Eating quickly can cause you to swallow air, which can cause belching or gas.

Adding fiber to your diet, especially if constipation is one of your main symptoms, can help to loosen stools and reduce abdominal pain. At first, fiber will increase the amount of gas in your system, so add fiber gradually. Over time, the body adjusts to the effects of fiber and the gassiness will decrease. Fruits, vegetables, and whole-grain bread and cereals are good food sources of fiber. Your doctor may recommend a fiber supplement. Some experts believe that the fiber methylcellulose creates the least amount of gas, and brands of this fiber are often recommended for people with IBS. Psyllium is also a good source of fiber.

If your symptoms are not relieved after you eliminate trigger foods and add fiber, your doctor may prescribe medications. Depending on what your most difficult symptoms are, medications can include:

  • Antidiarrheals –  loperamide (Imodium), diphenoxylate (Lomotil and other brand names)
  • Antispasmodics to reduce cramping –  dicyclomine (Bentyl)
  • Pain-reducing agents – amitriptyline (Elavil), desipramine (Norpramin)

Two other prescription medications are available for very severe symptoms that do not respond to other therapies. Both drugs have been studied primarily in women, so they have been approved by the FDA for use in women only. These medicines affect the peristalsis (motility) of the gastrointestinal tract by influencing the way the intestine reacts to the natural hormone serotonin. Women with constipation related to IBS can take tegaserod (Zelnorm) for several weeks at a time but must stop the medication for safety reasons if it results in cramps. Women with a history of bowel obstruction, active gallstones, severe kidney or liver impairment, active diarrhea, and bowel adhesions should not take Zelnorm. Alosetron (Lotronex) is used to treat women with IBS who have very severe diarrhea. If you take this medication, you have to receive it from a specialist with experience using the medication (the doctor must register with the drug manufacturer and receive training to be a prescriber) and you must sign a form stating that you are aware that life-threatening complications of a blocked, ruptured or damaged bowel may be caused by this medicine.

If you would like to look into endoscopic procedures to address your IBS, visit IES Medical Group to learn more about your options.

When To Call a Professional

It is useful for anyone with irritable bowel symptoms to discuss their symptoms with a doctor, so that diet, fiber, and drug treatment strategies can be planned.

After you have been diagnosed with irritable bowel syndrome, you should revisit with your doctor if you have an episode of severe symptoms. You should also see your doctor if you have blood in your stool; if abdominal pain is accompanied by vomiting, dizziness or fainting; if abdominal pain or diarrhea awakens you from sleep; or if you have unexplained weight loss or fever.


There is no cure for IBS, but symptoms can be managed by changing your diet, reducing stress, and, if necessary, taking medication. It is common for IBS to be a chronic problem, although it resolves in some individuals.