Irritable Bowel Syndrome

Key Facts
  • IBS can cause abdominal pain and stool changes such as constipation or diarrhea.
  • There are lots of treatments that can improve symptoms.
  • Esta guía en Español
  • Young men's version of this guide

Irritable Bowel Syndrome (IBS) is the most common gastrointestinal (digestive) disorder in the U.S. According to research studies, nearly 22-35.5% of adolescents have symptoms of IBS.

What is Irritable Bowel Syndrome (IBS)?

IBS is defined by a cluster of symptoms of abdominal pain occurring with a change in stooling pattern. “Stooling” and “having a bowel movement” are other ways of saying pooping. IBS is a condition that involves increased sensitivity of the gut and affects how the muscles in the intestines tighten. It is believed that the contractions may be too fast (causing diarrhea), slow (causing constipation), or go back and forth between both. That’s why it is called “irritable” bowel syndrome.

Symptoms may include:

  • Stomach pain
  • Constipation
  • Loose stools (diarrhea)
  • Both constipation & loose stools
  • Changing bowel habits
  • Bloating
  • Gas
  • White mucus in stool

What causes IBS?

Healthcare providers don’t know the exact cause of IBS. It is a functional disorder, meaning that there is a disconnect in the way that the brain and digestive system work together. Most people believe that a combination of problems may be responsible for the symptoms.

  • Extra sensitive organs in your digestive tract
  • Stressful events or feelings of anxiety or depression
  • A bacteria or infection in your digestive tract
  • Sensitivity or allergy to certain foods

How is IBS diagnosed?

IBS is diagnosed by a health care provider based on a person’s symptoms, their medical history, physical exam, blood work, and sometimes with the help of other diagnostic tests. These tests and other minor procedures may be done to make sure the symptoms are not caused by another medical problem. To be diagnosed with IBS, a person will typically have had a change in bowel movements and stomach pain/discomfort related to constipation and/or diarrhea for at least one day per week over the past 3 months with symptoms starting at least 6 months ago.

Tests may include:

  • Blood test(s) to check for infection and inflammation or other cause of symptoms such as celiac disease
  • Stool sample to check for parasite infections and the presence of blood in stool
  • Lactose breath hydrogen test- to find out if you have trouble digesting milk products
  • Abdominal x-ray to check internal organs and stool patterns
  • Abdominal ultrasound to check internal organs using soundwaves
  • Endoscopy to check for inflammation on the inside of the digestive tract.

Most of the time, not all of these tests are needed, and IBS can be diagnosed simply based on a patient’s symptoms and physical exam.

How is IBS treated?

The goal of the treatment is to decrease pain and to make the digestive process more normal. Treatment is started only after the diagnosis is made by a health care provider and can vary based on age, overall health, medical history, and how severe the symptoms (such as gas, bloating, diarrhea, constipation, stomach pain) are. There is no “cure” for IBS at this time but there are effective treatments to manage symptoms. Management of IBS symptoms often includes a combination of the following:

  • Meeting with a Registered Dietitian who specializes in gastrointestinal (GI) concerns
  • Limiting milk and milk products (if you are lactose intolerant)
  • Limiting other foods if you have a sensitivity
  • Learning how to effectively cope with stress and anxiety
  • Complementary therapies such as biofeedback, acupuncture, and yoga
  • Medicine (if necessary)
  • Counseling to help lower stress and anxiety

How can I find out if the foods I am eating are causing me to have IBS symptoms or making my IBS symptoms worse?

If you think that your IBS symptoms are related to different foods you are eating, the best way to find out more is to work with a Registered Dietitian. They can talk to you about certain dietary changes that have been studied that improve symptoms of IBS. You can get a better idea of how certain foods you are eating are affecting your symptoms by writing down what you eat and the symptoms that you have in a “food diary” (see sample below). You can also try logging your symptoms related to different foods on any symptom tracking application available for your phone.

With a dietitian, you can work on making changes to your eating after observing how your body responds to different foods.

  • If there’s a food that you think causes IBS symptoms most of the time, try to stop eating it for at least 2 weeks, and then try to slowly re-introduce small amounts again to see if you notice a change in your symptoms.
  • When logging your symptoms with food, be sure to include the amount of food eaten. This is because certain foods may only trigger symptoms for you if they are eaten in large amounts.
Sample Food Diary
Meal Food & Drink Symptoms Supplements
Breakfast Large bowl of Cheerios®, with ½ cup milk, whole banana, 2 eggs Gas, bloating Vitamin D
Snack One applesauce cup
Lunch Medium bowl of Macaroni & Cheese Gas, bloating, diarrhea
Snack small apple
Dinner ~4oz grilled Chicken, ½ cup of rice, and 4-5 baby carrots

Download a blank food diary sheet here. Make a copy for each day, and track what you ate and whether or not you had any symptoms.

What has been helpful to others with IBS?

People may react to foods differently but many individuals diagnosed with IBS find that certain foods tend to cause digestive distress or make symptoms worse. By working with a Registered Dietitian, you can try eliminating (removing from your diet) certain foods to see how your body responds and then gradually re-introduce foods that your body can tolerate. For example, your dietitian may work with you to see how you respond to certain types of foods, called FODMAPs.

Some strategies that a doctor or dietitian may recommend for people with IBS are listed below:

  • Avoid large meals. Instead, try eating smaller and more frequent meals and snacks.
  • Limit dairy and foods that contain lactose (if you notice worsening symptoms when you eat them). If your health care provider thinks you have an intolerance to dairy milk-based products, think about choosing lactose-free dairy products instead such as Lactaid®.
  • Limit artificial sweeteners such as sorbitol, mannitol, xylitol, and isomalt which are mainly found in sugarless gum and candy.
  • Limit high fructose corn syrup, agave, and honey (check the ingredients label). Instead, use maple syrup, brown sugar, or granulated white sugar when baking.

Is IBS the same as inflammatory bowel disease (IBD)?

No. IBD is an ongoing disease that is caused by the immune system fighting the digestive tract. It includes two different diseases, ulcerative colitis and Crohn’s disease.

Signs and symptoms of IBD are different than those of IBS and include:

  • Bloody diarrhea
  • Abdominal pain (in your stomach) that last a long time
  • Long-term watery diarrhea
  • Fevers for no reason
  • Joint swelling
  • Poor growth or a delay in puberty
  • Anal infections

IBS is different than IBD. With IBS the intestine is not inflamed and it almost never causes bloody diarrhea or blood in the stool.

What other ways can IBS affect me?

Irregular bowel habits can be frustrating and lead to emotional stress. Luckily there are healthy ways to lower your stress level, such as taking a proactive role in your treatment plan. For example, keeping track of what you eat so you can figure out what foods seem to trigger symptoms, doing activities that you enjoy and that help you to de-stress, and talking with a friend, parent, and/or counselor about your feelings.

Although IBS symptoms can be uncomfortable and stressful, most teens do not develop chronic health problems because of them. With the help of your health care provider and a registered dietitian, you can learn ways to make changes to your diet that can improve, or even get rid of, some or all of your symptoms.


Our health guides are developed through a systematic, rigorous process to ensure accuracy, reliability, and trustworthiness. Written and reviewed by experienced healthcare clinicians from Boston Children's Hospital, a Harvard Medical School teaching hospital and consistently ranked as a top hospital by Newsweek and U.S. News & World Report, these guides combine clinical expertise, specialized knowledge, and evidence-based medicine. We also incorporate research and best practices from authoritative sources such as the CDC, NIH, PubMed, top medical journals, and UpToDate.com. Clinical specialists and subject matter experts review and edit each guide, reinforcing our commitment to high-quality, factual, scientifically accurate health information for young people.