Irritable bowel syndrome (IBS) is a group of symptoms that occur together, including repeated pain in your abdomen and changes in your bowel movements, which may be diarrhea, constipation, or both. With IBS, you have these symptoms without any visible signs of damage or disease in your digestive tract.
IBS is a functional gastrointestinal (GI) disorder. Functional GI disorders, which doctors now call disorders of gut-brain interactions, are related to problems with how your brain and your gut work together. These problems can cause your gut to be more sensitive and change how the muscles in your bowel contract. If your gut is more sensitive, you may feel more abdominal pain and bloating. Changes in how the muscles in your bowel contract lead to diarrhea, constipation, or both.
Does IBS have another name?
In the past, doctors called IBS colitis, mucous colitis, spastic colon, nervous colon, and spastic bowel.
Are there different types of IBS?
Three types of IBS are based on different patterns of changes in your bowel movements or abnormal bowel movements. Sometimes, it is important for your doctor to know which type of IBS you have. Some medicines work only for some types of IBS or make other types worse. Your doctor might diagnose IBS even if your bowel movement pattern does not fit one particular type.
Many people with IBS have normal bowel movements on some days and abnormal bowel movements on other days.
IBS with constipation (IBS-C)
With IBS-C, on days when you have at least one abnormal bowel movement
more than a quarter of your stools are hard or lumpy and
less than a quarter of your stools are loose or watery
IBS with diarrhea (IBS-D)
In IBS-D, on days when you have at least one abnormal bowel movement
more than a quarter of your stools are loose or watery and
less than a quarter of your stools are hard or lumpy
IBS with mixed bowel habits (IBS-M)
In IBS-M, on days when you have at least one abnormal bowel movement
more than a quarter of your stools are hard or lumpy and
more than a quarter of your stools are loose or watery
How common is IBS?
Studies suggest that about 12 percent of people in the United States have IBS.1
Who is more likely to develop IBS?
Women are up to two times more likely than men to develop IBS.1 People younger than age 50 are more likely to develop IBS than people older than age 50.2
Factors that can increase your chance of having IBS include:
having a family member with IBS
a history of stressful or difficult life events, such as abuse, in childhood
having a severe infection in your digestive tract
What other health problems do people with IBS have?
People with IBS often have other health problems, including1
Women with IBS often have more symptoms during their periods.
IBS can be painful but doesn’t lead to other health problems or damage your digestive tract.
To diagnose IBS, you doctor will look for a certain pattern in your symptoms over time. IBS is a chronic disorder, meaning it lasts a long time, often years. However, the symptoms may come and go.
What causes IBS?
Doctors aren’t sure what causes IBS. Experts think that a combination of problems may lead to IBS. Different factors may cause IBS in different people.
Functional gastrointestinal (GI) disorders such as IBS are problems with brain-gut interaction—how your brain and gut work together. Experts think that problems with brain-gut interaction may affect how your body works and cause IBS symptoms. For example, in some people with IBS, food may move too slowly or too quickly through the digestive tract, causing changes in bowel movements. Some people with IBS may feel pain when a normal amount of gas or stool is in the gut.
Certain problems are more common in people with IBS. Experts think these problems may play a role in causing IBS. These problems include
stressful or difficult early life events, such as physical or sexual abuse
small intestinal bacterial overgrowth, an increase in the number or a change in the type of bacteria in your small intestine
food intolerances or sensitivities, in which certain foods cause digestive symptoms
Research suggests that genes may make some people more likely to develop IBS.
How do doctors diagnose IBS?
To diagnose irritable bowel syndrome (IBS), doctors review your symptoms and medical and family history and perform a physical exam. In some cases, doctors may order tests to rule out other health problems.
Review of your symptoms
Your doctor will ask about your symptoms and look for a certain pattern in your symptoms to diagnose IBS. Your doctor may diagnose IBS if you have pain in your abdomen along with two or more of the following symptoms:
Your pain is related to your bowel movements. For example, your pain may improve or get worse after bowel movements.
You notice a change in how often you have a bowel movement.
listens to sounds within your abdomen using a stethoscope
taps on your abdomen checking for tenderness or pain
What tests do doctors use to diagnose IBS?
In most cases, doctors don’t use tests to diagnose IBS. Your doctor may order blood tests, stool tests, and other tests to check for other health problems.
A health care professional will take a blood sample from you and send the sample to a lab. Doctors use blood tests to check for conditions other than IBS, including anemia, infection, and digestive diseases.
Your doctor will give you a container for catching and holding a stool sample. You will receive instructions on where to send or take the kit for testing. Doctors use stool tests to check for blood in your stool or other signs of infections or diseases. Your doctor may also check for blood in your stool by examining your rectum during your physical exam.
Doctors may perform other tests to rule out health problems that cause symptoms similar to IBS symptoms. Your doctor will decide whether you need other tests based on
blood or stool test results
whether you have a family history of digestive diseases, such as celiac disease, colon cancer, or inflammatory bowel disease
whether you have symptoms that could be signs of another condition or disease
colonoscopy to check for conditions such as colon cancer or inflammatory bowel disease
How do doctors treat IBS?
Doctors may treat irritable bowel syndrome (IBS) by recommending changes in what you eat and other lifestyle changes, medicines, probiotics, and mental health therapies. You may have to try a few treatments to see what works best for you. Your doctor can help you find the right treatment plan.
Changes to what you eat and other lifestyle changes
Changes in what you eat may help treat your symptoms. Your doctor may recommend trying one of the following changes:
Follow your doctor’s instructions when you use medicine to treat IBS. Talk with your doctor about possible side effects and what to do if you have them.
Your doctor may also recommend probiotics. Probiotics are live microorganisms, most often bacteria, that are similar to microorganisms you normally have in your digestive tract. Researchers are still studying the use of probiotics to treat IBS.
To be safe, talk with your doctor before using probiotics or any other complementary or alternative medicines or practices. If your doctor recommends probiotics, talk with him or her about how much probiotics you should take and for how long.
Mental health therapies
Your doctor may recommend mental health therapies to help improve your IBS symptoms. Therapies used to treat IBS include
soluble fiber, which is found in beans, fruit, and oat products
insoluble fiber, which is found in whole-grain products and vegetables
Research suggests that soluble fiber is more helpful in relieving IBS symptoms.
To help your body get used to more fiber, add foods with fiber to your diet a little at a time. Too much fiber at once can cause gas, which can trigger IBS symptoms. Adding fiber to your diet slowly, by 2 to 3 grams a day, may help prevent gas and bloating.
Your doctor may recommend avoiding foods that contain gluten—a protein found in wheat, barley, and rye—to see if your IBS symptoms improve. Foods that contain gluten include most cereal, grains, and pasta, and many processed foods. Some people with IBS have more symptoms after eating gluten, even though they do not have celiac disease.
Low FODMAP diet
Your doctor may recommend that you try a special diet—called the low FODMAP diet—to reduce or avoid certain foods that contain carbohydrates that are hard to digest. These carbohydrates are called FODMAPs.
Examples of foods that contain FODMAPs include
fruits such as apples, apricots, blackberries, cherries, mango, nectarines, pears, plums, and watermelon, or juice containing any of these fruits
canned fruit in natural fruit juice, or large amounts of fruit juice or dried fruit
vegetables such as artichokes, asparagus, beans, cabbage, cauliflower, garlic and garlic salts, lentils, mushrooms, onions, and sugar snap or snow peas
dairy products such as milk, milk products, soft cheeses, yogurt, custard, and ice cream
wheat and rye products
honey and foods with high-fructose corn syrup
products, including candy and gum, with sweeteners ending in “–ol,” such as sorbitol, mannitol, xylitol, and maltitol
Your doctor may suggest that you try the low FODMAP diet for a few weeks to see if it helps with your symptoms. If your symptoms improve, your doctor may recommend slowly adding foods that contain FODMAPs back into your diet. You may be able to eat some foods with FODMAPs without having IBS symptoms.
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions, including digestive diseases.
What are clinical trials for IBS?
Clinical trials—and other types of clinical studies—are part of medical research and involve people like you. When you volunteer to take part in a clinical study, you help doctors and researchers learn more about disease and improve health care for people in the future.
Researchers are studying many aspects of irritable bowel syndrome (IBS), such as
the relationship between the colon microbiome and IBS symptoms
genetic and neurological factors related to IBS
the development of IBS after an acute gastrointestinal infection
Watch a video of NIDDK Director Dr. Griffin P. Rodgers explaining the importance of participating in clinical trials.
What clinical studies for IBS are looking for participants?
You can view a filtered list of clinical studies on IBS that are federally funded, open, and recruiting at www.ClinicalTrials.gov. You can expand or narrow the list to include clinical studies from industry, universities, and individuals; however, the NIH does not review these studies and cannot ensure they are safe. Always talk with your health care provider before you participate in a clinical study.
What have we learned about IBS from NIDDK-funded research?
The NIDDK has supported many research projects to learn more about IBS. For example, an NIDDK-supported clinical trial found that a home-based version of cognitive behaviorally therapy led to significant and lasting improvement in IBS symptoms.
This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases
(NIDDK), part of the National Institutes of Health. The NIDDK translates and disseminates research findings to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by the NIDDK is carefully reviewed by NIDDK scientists and other experts.
The NIDDK would like to thank:
Lin Chang, M.D., David Geffen School of Medicine, University of California Los Angeles