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About Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome (IBS) is a chronic functional disorder of the GI tract.IBS affects approximately 10 –15% of adults and adolescents and is the most commonly diagnosed gastrointestinal condition. Primary symptoms are abdominal pain and altered bowel habits,but these symptoms have no identifiable cause.

Several treatments and therapies are available which help alleviate symptoms, but there is no cure. The chronic nature of IBS and the challenge of controlling its symptoms can be frustrating for both patients and healthcare providers.


Despite intensive research, the cause is not clear.Clinicians call it a functional disorder because there is no sign of disease when the colon is examined. IBS causes a great deal of discomfort and distress, but it does not cause permanent harm to the intestines, lead to intestinal bleeding of the bowel, or cause serious disease such as cancer.

Normal Bowel Function

Normal bowel function varies from person to person. Normal bowel movements range from as many as three stools a day to as few as three per week. A normal movement is one that is formed but not hard, contains no blood, and is passed without cramps or pain.


It is important to realize that normal bowel function varies from person to person. Normal bowel movements range from as many as three stools a day to as few as three a week. A normal movement is one that is formed but not hard, contains no blood, and is passed without cramps or pain.

Abdominal Pain

Abdominal pain is typically crampy and varies in intensity, ranges from mild to severe, and periodically has exacerbations.Defecation can improve or worsen pain. Emotional stress and meals may exacerbate the pain.

Changes in bowel habits 

This can include diarrhea, constipation, alternating diarrhea and constipation, or normal bowel habits alternating with either diarrhea and/or constipation. Large volumes of diarrhea, bloody stools, waking in the middle of the night to have a BM, and greasy stools are not common with IBS.


Characterized by frequent loose stools, small to moderate volume,that usually occur during the daytime, most often in the morning or after meals. Diarrhea is often preceded by lower abdominal cramping, urgency, and followed by a feeling of incomplete emptying. About one-half of people with IBS also notice mucous discharge with stools.


Stools that are hard and pellet-shaped. You may not feel completely empty after a bowel movement even when the rectum is empty.

Other symptoms 

Other symptoms of IBS include bloating, gas, and belching.


Several intestinal disorders have symptoms that are similar to IBS. There is no single diagnostic test for irritable bowel syndrome. A medical history, physical examination, and select tests can help rule out other medical conditions. The clinician also may do diagnostic procedures such as x-rays or colonoscopy (viewing the colon through a flexible tube inserted through the anus) to find out if there is another disease process causing the abdominal pain.

Non-Medication Treatment

Treatment is usually a long-term process. Mild symptoms are usually aimed at dietary modification, while more symptomatic or severe cases are treated with medication. Treatments are often combined to reduce the pain and other symptoms of IBS, and it may be necessary to try more than one combination to find the one that is most helpful for you. Communicate with your healthcare provider about symptoms, concerns, and any stressors or home/work/family problems that develop during your treatment.

Monitor symptoms 

The first step in treating IBS is usually to monitor symptoms by tracking diet, bowel habits, and any other factors that may affect your bowels. This can help to identify factors that worsen symptoms in some people with IBS, such as lactose or other food intolerances, and stress.

Diet modification 

Patients with IBS may benefit from exclusion of gas-producing foods, a diet low in fermentable/poorly absorbed carbohydrates (FODMAPs), and in select cases, lactose,and/or gluten avoidance.Fiber can also be recommended in the appropriate situation.

Foods that cause gas

Eliminating these foods are reasonable if gas or bloating is bothersome.

  • The most common gas-producing foods are legumes (such as beans) and cruciferous vegetables (such as cabbage, Brussels sprouts, cauliflower, and broccoli).
  • In addition, some people have trouble with onions, celery, carrots, raisins, bananas, apricots, prunes, sprouts, and wheatgerm, pretzels, and bagels.
  • Alcohol and caffeine should be avoided.


Shortened named for“fermentable oligosaccharides, disaccharides, monosaccharides and polyols” diet. This diet is aimed at reducing/avoiding certain foods that contain carbohydrates that are hard to digest. It includes 3 phases: elimination, reintroduction, and personalization. FODMAPs diet takes several weeks to implement and should be guided by a dietician.


Foods to avoid or limit on FODMAP diet

(High FODMAP diet)

Foods to eat on FODMAP diet

(Low FODMAP diet)

Fruit Apples, apricots, cherries, mango, nectarines, pears, peaches, pears, plums, prunes, watermelon, canned fruit, dried fruit, fruit juice Banana, blueberries, cantaloupe, grapefruit, grapes, honeydew melon, kiwi, lemon, lime, mandarin oranges, orange, passionfruit, raspberries, strawberries
Vegetables Artichokes, asparagus, avocado, beets, broccoli, Brussel sprouts, cabbage, cauliflower, gargle (large quantity), fennel, leeks, mushrooms, okra, onions, pears, radicchio, lettuce, scallions (white parts), shallots, sugar snap pears, snow peas Bell peppers, bok choy, carrots, celery, corn, eggplant, green beans, lettuce, parsnips, pumpkin, scallions (green part), spinach, sweet potato, white potato, squash, tomato, yam, zucchini
Dairy Custard, ice cream, margarine, milk (cow, goat, sheep), soft cheeses (including ricotta and cottage), yogurt Butter, hard cheese, brie, camembert, lactose-free products such as lactose-free ice cream, yogurt, gelato, rice milk and sorbet, eggs
Grains Wheat or rye in large amts, including bread, crackers, cookies, cous cous, pasta, etc. Gluten-free products, oats, polenta, rice, quinoa, tapioca
Legumes Baked beans, chickpeas, lentils, kidney beans, soybeans  
Sweeteners Honey, fructose, high fructose corn syrup, isomalt, maltitol, mannitol, sorbitol, xylitol Artificial sweeteners that did not end in “ol”, glucose, maple syrup, molasses, sugar (sucrose)
Other Chicory, dandelion, pistachio Meats




A lactose-restricted diet should be considered for those who experience persistent abdominal bloating despite exclusion of gas-producing products. Although the incidence of lactose malabsorption is not higher in patients with IBS, patient with IBS and lactose intolerance can have an exaggerated symptom response to lactose ingestion.

  • The greatest concentration of lactose is found in milk and ice cream, although it is present in smaller quantities in yogurt, cottage and other cheeses, and any prepared foods that contain these ingredients. 
  • All lactose containing products should be eliminated for two weeks. If IBS symptoms improve, it is reasonable to continue avoiding lactose. If symptoms do not improve, you may resume eating lactose-containing foods.


Gluten has been demonstrated to alter bowel barrier functions with patients with IBS-D. Evidence to support gluten avoidance in patients with IBS has been conflicting though.

Increasing dietary fiber 

The role of fiber is controversial but given lack of serious side effects and potential benefit, it may be used in patients whose predominant complaint is constipation.

  • A bulk-forming fiber supplement (such as psyllium or methylcellulose)may be recommended to increase fiber intake if it is difficult to consume enough fiber in your diet.
  • Fiber supplements should be started at a low dose and increased slowly over several weeks to reduce the side effects of excessive intestinal gas and bloating, which can occur in some people during the beginning of fiber therapy. A starting dose of ½ to 1 tablespoon daily is recommended, then titrated up based on response.
Psychosocial therapies 

Stress and anxiety can worsen IBS symptoms in some people. The best approach for reducing stress and anxiety depends upon your situation and the severity of your symptoms. Have an open discussion with your clinician about the possible role that stress, and anxiety could be having on your symptoms, and together decide upon the best course of action.

  • Some people benefit from formal counseling, with or without antidepressant or antianxiety medications. Cognitive behavioral therapy helps you to focus on a particular problem in a limited time period. You learn how your thoughts contribute to anxiety or stress and learn how to change these thoughts.
  • Participation in a support group can also be valuable.
  • Many patients find daily exercise to be helpful in maintaining a sense of well-being. Exercise can also have favorable effects on the bowels, therefore, 20 –60 minutes, 3 –5 times per week of moderate to vigorous intensity exercise is recommended.


Although many drugs are available to treat the symptoms of IBS, these drugs do not cure the condition. The choice among these medications depends in part upon whether you have diarrhea, constipation, or pain-predominant irritable bowel syndrome.As a general rule, medications are reserved for people whose symptoms have not adequately responded to more conservative measures such as changes in diet or fiber supplements and suffer from moderate to severe symptom severity.

Anticholinergic medications

Anticholinergic drugs block the nervous system's stimulation of the gastrointestinal tract, helping to reduce severe cramping and irregular contractions of the colon.

Antidepressant/Anti-anxiety medication

Tricyclic antidepressants (TCAs) have a pain-relieving effect in people with IBS. The dose of TCAs is typically much lower than that used for treating depression. It is believed that these drugs reduce pain perception when used in low doses, although the exact mechanism of their benefit is unknown.TCAs also slow movement of contents through the gastrointestinal tract and may be most helpful in people with diarrhea-predominant irritable bowel syndrome.Should be used cautiously in patients with constipation.

Selective Serotonin Reuptake Inhibitors, another class of antidepressants, may be recommended if you have both IBS and depression.

Osmotic Laxatives

Suggested for patients with constipation who fail a trial of soluble fiber. Polyethylene Glycol (PEG)is inexpensive, widely available, and has few side effects compared to other medications such as Milk of Magnesia. Side effects can include bloating and abdominal discomfort. These medications often help with constipation but not abdominal pain.

Antidiarrheal drugs

The drugs loperamide(Imodium®) or diphenoxy late with atropine(Lomotil®) can help slow the movement of stool through the digestive tract by inhibiting movement, prolonging transit time, and reducing fecal volume.Clinicians usually recommend these drugs be used on an as needed basis rather than continuously.

Bile acid sequestrants

Second line therapy for IBS-D, after anti-diarrheal drugs.Such rational is based on the suggestion that 50% of patients with a diagnosis of functional diarrhea and IBS-D have bile acid malabsorption. Bile acids cause diarrhea by stimulating colonic secretion and motility. Medications in this category can be limited by side effects including bloating, flatulence, abdominal discomfort, and constipation.

Antispasmodic agents

Provide short term relief of abdominal pain in patients with IBS, but their long-term efficacy has not been established. They are used on an as-needed basis and/or in anticipation of stressors with known exacerbating effects.

Other Medications

Sometimes there are specific drugs prescribed by a Gastroenterologist that may be used if your symptoms are not responsive to the previously mentioned treatments. The role of antibiotics remains unclear. Probiotics are not routinely recommended in patients with IBS, although they have been associated with an improvement in symptoms. The most effective species/strains and extent of benefit remain unclear.

Herbs and Natural Therapies


Several herbal and natural therapies have been advertised for the treatment of IBS. Unfortunately, there is no significant evidence supporting their benefit.


Although IBS can produce substantial physical discomfort and emotional distress, most people with IBS do not develop serious long-term health conditions. Furthermore, the vast majority of people with IBS learn to control their symptoms.

Call the UHS advice nurse if any of the following happens:

  • Fever
  • Bleeding
  • Weight loss
  • Persistent severe pain
  • Nighttime diarrhea
  • Worsening of symptoms


In an emergency go to Mount Nittany Medical Center or call 911 for an ambulance.

Test Results and Advice Nurse

Send a secure message to the advice nurse via myUHS or call 814-865-4UHS (4847) (Press 3). 


Schedule an appointment online or by calling the UHS.  

This content is reviewed periodically and is subject to change as new health information becomes available. This information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis, or treatment by a healthcare professional.

Approved by the UHS Patient Education Committee Revised 06/10/2020

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Irritable Bowel Syndrome


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