Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a common intestinal condition characterized by abdominal pain and cramps; changes in bowel movements (diarrhea, constipation, or both); gassiness; bloating; nausea; and other symptoms.

There is no recognized cure for IBS. Much about the condition remains unknown or poorly understood; however, dietary changes, drugs, and psychological treatment are often able to eliminate or substantially reduce its symptoms.

IBS is the name people use today for a condition that was once called colitis, spastic colon, nervous colon, spastic bowel, and functional bowel disorder. Some of these names reflected the now-outdated belief that IBS is a purely psychological disorder and a product of the patient’s imagination.

Although modern medicine recognizes that stress can trigger IBS attacks, medical specialists agree that IBS is a genuine physical disorder or group of disorders with specific identifiable characteristics.

No one knows for sure how many Americans suffer from IBS. Surveys indicate a range of 10-20%, with perhaps as many as 30% of Americans experiencing IBS at some point in their lives.

IBS normally makes its first appearance during young adulthood, and in half of all cases, symptoms begin before age 35. Women with IBS outnumber men by two to one, for reasons not yet understood.

IBS is responsible for more time lost from work and school than any medical problem other than the common cold. It accounts for a substantial proportion of the patients seen by gastroenterologists, who are specialists in diseases of the digestive system. Yet only half—possibly as few as 15%—of IBS sufferers ever consult a doctor.

Causes and symptoms

Irritable Bowel Syndrome

The symptoms of IBS tend to rise and fall in intensity rather than grow steadily worse over time. They always include intestinal (abdominal) pain that may be relieved by defecation; diarrhea or constipation; or diarrhea alternating with constipation.

Other symptoms, which vary from person to person, include cramps, gassiness, bloating, nausea, a powerful and uncontrollable urge to defecate (urgency), passage of a sticky fluid (mucus) during bowel movements, or the feeling after finishing a bowel movement that the bowels are still not completely empty. The accepted diagnostic criteria, known as the Rome criteria, require at least three months of continuous or recurrent symptoms before IBS is diagnosed.

According to Christine B. Dalton and Douglas A. Drossman in the American Family Physician, an estimated 70% of IBS cases can be described as “mild”; 25% as “moderate”; and 5% as “severe.” In mild cases the symptoms are slight. As a general rule, they are not present all the time and do not interfere with work and other normal activities.

Moderate IBS disrupts normal activities and may cause some psychological problems. People with severe IBS may constantly fear the unpredictable need for a bathroom. They often find living a normal life impossible and experience crippling psychological problems as a result. For some, the physical pain is constant and intense.


Researchers remain unsure about the cause or causes of IBS. It is called a functional disorder because it is thought to result from changes in the activity of the major part of the large intestine (the colon). After food is digested by the stomach and small intestine, the undigested material passes in liquid form into the colon, which absorbs water and salts.

This process may take several days. In a healthy person the colon is quiet during most of that period except after meals, when its muscles contract in a series of wavelike movements called peristalsis. Peristalsis helps absorption by bringing the undigested material into contact with the colon wall.

It also pushes undigested material that has been converted into solid or semisolid feces toward the rectum, where it remains until defecation. In IBS, however, the normal rhythm and intensity of peristalsis is disrupted.

Sometimes there is too little peristalsis, which can slow the passage of undigested material through the colon and cause constipation. Sometimes there is too much, which has the opposite effect and causes diarrhea.

A Johns Hopkins University study found that healthy volunteers experienced six to eight contractions of the colon each day, compared with up to 25 contractions a day for volunteers suffering from IBS with diarrhea, and an almost complete absence of contractions among constipated IBS volunteers.

In addition to differences in the number of contractions, many of the IBS volunteers experienced powerful spasmodic contractions affecting a larger-than-normal area of the colon—“like having a Charlie horse in the gut,” according to one of the investigators.

DIET. Some kinds of food and drink appear to play a key role in triggering IBS attacks. Food and drink that healthy people can ingest without any trouble may disrupt peristalsis in IBS patients, which probably explains why IBS attacks often occur shortly after meals. Chocolate, milk products, caffeine (in coffee, tea, colas, and other drinks), and large quantities of alcohol are some of the chief culprits.

Other kinds of food have also been identified as problems, however, and the pattern of what can and cannot be tolerated is different for each person. Characteristically, IBS symptoms rarely occur at night and disrupt the patient’s sleep.

In 2002 a research study reported that some children had trouble absorbing certain sugars from some fruit juices, particularly apple and pear juices. When children with IBS went off these juices for one month, 46% saw improvement in their IBS symptoms.

Apple and pear juice contain more fructose than glucose sugar, which may be the cause of the poor absorption in IBS sufferers’ intestines. Yet white grape juice, which contains almost equal portions of fructose and glucose, is more easily absorbed.

STRESS. Stress is an important factor in IBS because of the close nervous system connections between the brain and the intestines. Although researchers do not yet understand all of the links between changes in the nervous system and IBS, they point out the similarities between mild digestive upsets and IBS.

Just as healthy people can feel nauseated or have an upset stomach when under stress, people with IBS react the same way, but to a greater degree. Finally, IBS symptoms sometimes intensify during menstruation, which suggests that female reproductive hormones are another trigger.

In fact, a study published in 2002 confirmed that IBS symptoms worsened in women and that rectal sensitivity changed with the menstrual cycle in women with IBS. It also was the first study to contrast these changes with those in healthy women.


Diagnosing IBS is a fairly complex task because the disorder does not produce changes that can be identified during a physical examination or by laboratory tests. When IBS is suspected, the doctor (a family doctor or a specialist) needs to determine whether the patient’s symptoms satisfy the Rome criteria.

The doctor rules out other conditions that resemble IBS, such as Crohn’s disease and ulcerative colitis. These disorders are ruled out by taking a standard medical history, performing a physical examination, and ordering laboratory tests.

The patient may be asked to provide a stool sample that can be tested for blood and intestinal parasites. In some cases x-rays, bowel studies, or an internal examination of the colon using a flexible instrument inserted through the anus (a sigmoidoscope or colonoscope) is necessary.

Patients may also be asked to keep a diary of symptoms for two or three weeks, covering daily activities including meals and emotional responses to events. The doctor can then review the diary with the patient to identify possible problem areas.


Dietary adjustments are critical to controlling IBS. For some patients, a high-fiber diet including whole grain breads and cereals, dried and fresh fruits, spinach, and oat bran can reduce digestive system irritation.

For others, a high-fiber diet aggravates the symptoms. Many patients with IBS also find that avoiding alcohol, caffeine, sugar, and fatty, gas-producing, or spicy foods can prevent symptoms.

To control IBS symptoms that are triggered or made worse by stress, several stress management therapies may be helpful. These include yoga, meditation, hypnosis, biofeedback, exercise, muscle relaxation training, aromatherapy, hydrotherapy, and reflexology.

Reflexology is a foot massage technique that focuses on manipulating different regions of the foot in order to bring harmony to specific organs and body systems. Hydrotherapy is the therapeutic use of water, as in a whirlpool bath.

Biofeedback, which teaches an individual to control muscle tension and any associated pain through thought and visualization techniques, is also a treatment option for IBS.

In biofeedback treatments, sensors placed on the forehead of the patient are connected to a special machine that allows the patient and healthcare professional to monitor a visual and/or audible readout of the level of muscle tension and stress in the patient.

Through relaxation and visualization exercises, the patient learns to relieve tension and can actually see or hear the results of his or her efforts instantly through a sensor readout on the biofeedback equipment.

Once the technique is learned and the patient is able to recognize and differentiate between the feelings of muscle tension and muscle relaxation, the biofeedback equipment itself is no longer needed and the patient has a powerful, portable, and self-administered treatment tool to deal with pain and tension.

To soothe an irritated or inflamed digestive tract, an herbalist or holistic healthcare practitioner may recommend one or more herbs, including comfrey root (Symphytum officinale), hops (Humulus lupulus), Iceland moss (Cetraria islandica), Irish moss (Chondrus crispus), marsh mallow root (Althaea officinalis), oats (Avena sativa), quince seed (Cydonia oblonga), and slippery elm (Ulmus rubra).

Herbs that relieve gas associated with IBS (known as carminatives) include angelica (Angelica archangelica), aniseed (Pimpinella anisum), caraway (Carum carvi), cayenne (Capsicum annuum), German chamomile (Matricaria recutita), ginger (Zingiber officinale), thyme (Thymus vulgaris), and peppermint (Menthapiperata ).

An infusion of meadowsweet (Filipendula ulmaria) may be helpful in treating diarrhea related to IBS, and herbs such as barberry (Berberis vulgaris), psyllium ovata seed, dandelion root (Taraxacum officinale), licorice (Glycyrrhiza glabra), and yellow dock (Rumex crispus) have laxative properties that can help to relieve constipation.

More powerful laxative herbs, such as rhubarb root (Rheum palmatum), buckthorn (Rhamnus catharticus), and cascara (Rhamnus purshiana) should only be taken under the direction of a healthcare professional.

Individuals with cramp-like pains, or colic, can benefit from antispasmodic herbs such as German chamomile (Matricaria recutita), Valerian (Valeriana officinalis), lemon balm (Melissa officinalis), ginger (Zingiber officinale), and wild yam (Dioscorea villosa).

Homeopathy uses highly-diluted remedies that cause similar effects to the symptoms they are intended to treat in an effort to stimulate the body’s natural immune response.

A homeopathic physician might recommend a remedy of belladonna, colocynthis (bitter cucumber), phosphate of magnesia (Magnesia phosphorica), or wild hops (Bryonia alba) to relieve abdominal pain and cramping associated with IBS. As with all homeopathic remedies, the prescription depends on the individual’s overall symptoms, mood, and temperament.

Acupuncture and guided imagery may be useful tools in treating IBS symptoms. Acupuncture involves the placement of thin needles into the skin at targeted locations on the body known as acupoints in order to harmonize the energy flow within the human body.

An acupuncturist may also use moxibustion, which involves applying a heat source such as warm herbs to the acupoint, to treat IBS symptoms. Guided imagery techniques teach the patient to visualize a peaceful, soothing scene or situation to relax the body and better cope with the discomfort caused by IBS.

Allopathic treatment

Dietary changes, sometimes supplemented by drugs or psychotherapy, are considered the key to successful treatment. A drug called alosetron (Lotronex) was approved by the Food and Drug Administration (FDA) in 2002 for limited marketing for treating women with diarrhea-prominent IBS after some controversy in 2000 because of serious side effects from the drug.

Its use should be limited to only those patients suffering from severe, chronic diarrhea-predominant IBS who have failed to respond to conventional therapy.

An individualized diet, low in saturated fats and foods that trigger the patient’s reaction, can reduce symptoms for many IBS sufferers. Caffeine sources, sugar, and alcohol usually worsen symptoms. Bran or 15-25 grams a day of an over-the-counter psyllium laxative may also help both constipation and diarrhea.

The patient can have milk or milk products if lactose intolerance is not a problem. Establishing set times for meals and bathroom visits may help people with irregular bowel habits, especially for constipated patients.

Although a high-fiber diet remains the standard treatment for constipated patients, such laxatives as lactulose or sorbitol may be prescribed. Loperamide and cholestyramine are suggested for diarrhea. Abdominal pain after meals can be reduced by taking antispasmodic drugs such as hyoscyamine or dicyclomine before eating.

Psychological counseling or behavioral therapy may be useful for some patients to reduce anxiety and to learn to cope with the pain and other symptoms of IBS. Relaxation therapy, hypnosis, biofeedback, and cognitive-behavioral therapy are examples of behavioral therapy.

When IBS produces constant pain that interferes with everyday life, antidepressant drugs can help by blocking pain transmission from the nervous system.

Expected results

IBS is not a life-threatening condition. It does not cause intestinal bleeding or inflammation, nor does it cause other bowel diseases or cancer. Although IBS can last a lifetime, in up to 30% of cases the symptoms eventually disappear.

Even if the symptoms cannot be eliminated, with appropriate treatment they can usually be decreased so that IBS becomes merely an occasional inconvenience. Treatment requires a long-term commitment, however; six months or more may be needed before the patient notices substantial improvement.