Irritable bowel syndrome (IBS) is a condition that affects your lower gastrointestinal (GI) tract. This includes the small intestine and large intestine (colon). It is diagnosed when a person has belly pain or spasm associated with a change in the appearance or frequency of their bowel movements. It causes:

• Belly cramps.
• Gas.
• Swelling or bloating.
• Changes in your bowel habits, such as diarrhea or constipation.

When you have IBS, your colon looks normal. But it does not work the way it should.

Health experts have not been able to find an exact physical cause for IBS. It is often thought that stress is one cause. Stress may also make IBS symptoms worse.

IBS is a long-term, chronic condition. It can be painful. But it doesn't cause lasting harm to your intestines. And it doesn't lead to serious disease, such as cancer.

There is no link between IBS and Crohn's disease, ulcerative colitis, or other inflammatory bowel diseases. But people with inflammatory bowel disease can also have IBS.

The exact cause of IBS isn't known. There are many possible causes of IBS, and they differ from person to person. This means that some people can have the same symptoms but different causes of their IBS. Some experts think that if you have IBS, your colon or small intestine may be more sensitive than normal. That means it has a strong reaction to things that should not normally affect it.

When you have IBS, your colon muscles begin to move and tighten uncontrollably (spasm) after only mild stimulation or after normal events, such as:

• Eating.
• Swelling or bloating from gas or other material in the colon.
• Some medicines.
• Some foods.

Females with IBS seem to have more symptoms during their periods. This could mean that the hormones released during the menstrual cycle may increase IBS symptoms.

Some things can make IBS symptoms worse. The two things most likely to make your IBS symptoms worse are the foods you eat and having emotional stress.

• Diet. Eating makes your colon muscles move or contract. This normally gives you an urge to have a bowel movement 30 to 60 minutes after a meal. Having fat in your diet can cause contractions in your colon after a meal. With IBS, the urge may come sooner. You may also have cramps or diarrhea. Common foods that cause IBS are dairy products with lactose and poorly digested carbohydrates called FODMAPs (fermentable fructans, oligosaccharides, disaccharides, monosaccharides, and polyols).
• Stress. If you have IBS, stress can make your colon move uncontrollably or spasm. Experts don't fully understand why. But they believe this happens because the colon is partly controlled by the brain and spinal cord (nervous system). The nervous system controls how your body moves and reacts to things. Getting counseling or therapy and trying to lower your stress can help ease IBS symptoms. But this doesn't mean that IBS is caused by a mental or emotional condition. IBS is caused in part because of a problem with how the muscles of the colon move.

You are more likely to be at risk for IBS if you:

• Are young. In most cases, IBS starts before age 45.
• Are female. Females have IBS almost twice as often as males.
• Have had recent gastroenteritis.

Each person's symptoms may vary. Some of the most common symptoms include:

• Belly pain.
• Painful constipation or diarrhea.
• Switching back and forth between constipation and diarrhea.
• Having mucus in your stool.

Other health problems can cause symptoms similar to IBS. Always see your doctor to be sure. IBS does not cause rectal bleeding. Discuss any bleeding with your doctor.

Your doctor will ask about your past health and do a physical exam. You may not need any specific testing. Your provider will decide how much testing you need based on your age and symptoms. They may also do lab tests to check for infection and for redness and swelling (inflammation).

There are usually no physical signs to tell for sure that you have IBS. There are also no exact tests for IBS.

Your doctor may do lab tests and imaging tests to make sure that you don't have other health problems. These tests may include:

• Blood tests. These are done to see if you are lacking healthy red blood cells (anemia) or have an infection, celiac disease, or an illness caused by inflammation or irritation.
• Urinalysis and urine culture. These help to see if you have an infection in any part of your urinary system (urinary tract infection, or UTI). This includes your kidneys, the tubes that send urine from the kidneys to the bladder (ureters), your bladder, and your urethra, where urine leaves your body.
• Stool sample for infection. This test checks for any abnormal bacteria or parasites in your digestive tract that may cause diarrhea and other problems. To do this, a small stool sample is taken and sent to a lab. The stool can also be checked for other infections. This can be done by stool culture or other methods.
• Stool testing for blood (fecal immunochemical test). This test checks for hidden blood in your stool that can only be seen with a microscope. A small amount of stool is tested in a lab. If blood is found, it may mean you have redness and swelling (inflammation) in your gastrointestinal (GI) tract.
• Stool testing for inflammation. Checking stool levels of calprotectin or lactoferrin is common to determine if your intestine is inflamed.
• Stool testing for fat in the stool or an enzyme that is used to assess exocrine pancreatic function. Abnormal results may be a sign of a problem with the pancreas (exocrine pancreatic insufficiency). The condition is treated with pancreatic enzyme supplements.
• Upper endoscopy, also called esophagogastroduodenoscopy. This test looks at the inside, or lining, of your esophagus and stomach and the top part of your small intestine (duodenum). This test uses a thin, lighted tube called an endoscope. The tube has a camera at one end. The tube is put into your mouth and throat. Then it goes into your esophagus, stomach, and duodenum. Your doctor can see the inside of these organs. The doctor can also take a small tissue sample (biopsy), if needed.
• Abdominal X-rays, CT scan, or MRI. These tests make images of your internal tissues, bones, and organs. They are not required to diagnose IBS. Your doctor may order these tests to make sure your symptoms are not caused by certain other problems.
• Abdominal ultrasound (sonogram). If your symptoms seem like they may be coming from the liver or gallbladder area, an ultrasound can check. It can also check how blood is flowing through different blood vessels.
• Colonoscopy. This test looks at the full length of your large intestine. It can help check for any abnormal growths, red or swollen tissue (inflammation), sores (ulcers), or bleeding. A long, flexible, lighted tube called a colonoscope is put into your rectum and up into the colon. This tube lets your doctor see the lining of your colon and take out a tissue sample (biopsy) to test it. The doctor may also be able to treat some problems that may be found.
• Breath test. This test may diagnose bacterial overgrowth in the intestines that some believe can lead to or mimic the symptoms of IBS.

Treatment depends on your symptoms, age, and general health. It also depends on how severe the condition is.

Treatment for IBS may include:

• Changes in your eating habits. Changing the foods you eat is important if you have IBS. In some cases, a high-fiber diet can reduce symptoms. Some people get symptoms from lactose and should eat lactose-free dairy products. Some people get symptoms from poorly digestible carbohydrates and fructose. Some people are intolerant to gluten even though they may not have celiac disease. Many people with IBS get symptoms from large and fatty meals. Keep a list of foods that cause you pain, and talk about this with your doctor. Also talk with your doctor about FODMAPs and ways to reduce or remove them from your eating plan.
• Medicines. Your doctor may prescribe fiber supplements or have you take something now and then to loosen your stool (a laxative). Different medicines are used for IBS, depending on your symptoms. They include medicines to prevent constipation, diarrhea, pain, and spasm.
• Antibiotics. A poorly absorbed antibiotic is used in certain situations to improve IBS symptoms, especially symptoms of bloating, distention, and loose stool.
• Natural supplements. Some people feel better on various natural supplements called probiotics. Others get relief with peppermint oil capsules. Discuss any use of probiotics with your doctor.
• Stress management. Hypnosis, acupuncture, cognitive behavioral therapy, yoga, regular exercise, relaxation, and other mindfulness activities can help some people with IBS.

Good fiber sources may include:

The diarrhea and constipation that happen with IBS can cause hemorrhoids. If you already have hemorrhoids, they may get worse.

Your quality of life may be affected by IBS, as the symptoms may limit your daily activities. IBS is a common cause of disability.

Health experts don't know what causes IBS. They also don't know how to stop it from happening.

IBS symptoms can affect your daily activities. It's important to work with your doctor to manage the disease. You may need a plan to deal with issues, such as eating habits, work, lifestyle, and emotional or mental health.

Contact your doctor right away if your symptoms get worse or if you have new symptoms.

• IBS is a condition that affects your lower GI tract. This includes the small intestine and large intestine (colon).
• It is a long-term, chronic condition.
• The exact cause of IBS is not known. There are probably many different causes in different people.
• When you have IBS, your colon looks normal. But it doesn't work the way it should.
• The things most likely to make symptoms of IBS worse are your eating habits and emotional stress.
• Treatment may include changing your eating habits and taking medicines.

Here are some tips to help you get the most from a visit to your doctor.

• Know the reason for your visit and what you want to happen.
• Before your visit, write down questions you want answered.
• Bring someone with you to help you ask questions and remember what your doctor tells you.
• At the visit, write down the name of any new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your doctor gives you.
• Know why a new medicine or treatment is prescribed and how it will help you. Also know what the side effects are.
• Ask if your condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if you do not take the medicine or have the test or procedure.
• If you have a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your doctor if you have questions, especially after office hours or on weekends and holidays.