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Irritable Bowel Syndrome (IBS)

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Definition & Facts

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.

Symptoms & Causes

The most common symptoms of irritable bowel syndrome (IBS) are pain in your abdomen, often related to your bowel movements, and changes in your bowel movements. These changes may be diarrhea, constipation, or both, depending on what type of IBS you have. Doctors aren’t sure what causes IBS.


To diagnose irritable bowel syndrome (IBS), doctors review your symptoms and your medical and family history and perform a physical exam. Your doctor will look for a certain pattern in your symptoms. In some cases, doctors may order tests to rule out other health problems.


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.

Eating, Diet, & Nutrition

Your doctor may recommend changes in your diet to help treat symptoms of irritable bowel syndrome. Changes may include eating more fiber, avoiding gluten, or following a special diet called the low FODMAP diet. Different changes may help different people with IBS.

Clinical Trials

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.

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 through its clearinghouses and education programs 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