Irritable bowel syndrome (IBS) is a common digestive problem. Many people have symptoms of IBS (such as diarrhea, constipation, bloating, and belly pain) and never see a doctor about them. Other people may choose to see a doctor because they are concerned about their symptoms or because the symptoms are affecting their life.

It is not clear what causes irritable bowel syndrome, and the cause may be different for different people. Some ideas about what causes IBS include problems with the way signals are sent between the brain and the digestive tract , problems digesting certain foods, and stress or anxiety. People with IBS may have unusually sensitive intestines or problems with the way the muscles of the intestines move.

There are no tests that can diagnose IBS. Instead, experts use a set of criteria that help your doctor decide whether you may have IBS. Your doctor will likely ask you a lot of questions about your symptoms to see how well your symptoms match these criteria.

Treating the symptoms of IBS can improve your quality of life. But even with good treatment, you may still have some symptoms.

If you have tests, your doctor will decide which ones to do based in part on which symptoms bother you the most. For example, if you have diarrhea, your doctor may test your blood to see if you have a condition called celiac disease.

At your first visit, your doctor may recommend some of these tests:

• Medical history and physical examination
• A blood test for celiac disease, which may be considered if you have diarrhea as your most common IBS symptom
• Tests for lactose intolerance. Taking a breath test or trying a lactose-free diet may show that you have trouble digesting lactose.
• Blood tests. They can show an illness or infection.
• Stool analysis, which may include testing for blood in the stool (fecal occult blood test), infection (stool culture), or parasites (ova and parasites test)

Your doctor may also recommend other tests not in this list, such as imaging tests (for example flexible sigmoidoscopy or colonoscopy). Whether you have tests before you try home treatment may depend on your age and health history and which tests your doctor uses the most.

If you have an abnormal test result, it may mean that you have a problem other than IBS. You also may have both IBS and another problem.

Treatment usually includes making changes to your diet and lifestyle. You may try to:

• Increase the fiber in your diet. Try to eat more fresh fruits (such as raspberries, pears, and apples) and fresh vegetables (such as peas). Also try to eat more whole-grain breads and cereals.
• Avoid or limit gas-producing foods or drinks. These include beans and cabbage, sugarless chewing gum and candy, caffeine, and alcohol.
• Lower stress.
  • Get regular exercise.
  • Keep a journal or diary of events in your life to try to find a link between stress and your symptoms.
  • Enjoy hobbies and other activities to help you relax.
  • Get counseling if you need help to lower your stress.

If your tests are all normal and your symptoms match the symptoms that are common in people with IBS, you may feel reassured that you don't have a serious problem. You and your doctor can then focus on treating your symptoms so that they don't interfere with your life.

If the tests find that you have another problem, you and your doctor will make a plan to treat it.

Most tests have some risks. But the chance of a serious problem from a test is low.

Some of the tests, such as flexible sigmoidoscopy or colonoscopy, may be uncomfortable. People with IBS may find these tests more uncomfortable than do people who don't have IBS.

There is usually little risk in not having tests if your symptoms match those of IBS. The more of these symptoms you have, the more likely it is that you have IBS.

If you have a more serious problem, your symptoms are likely to get worse.

"Alarm symptoms" also may show that you have a more serious problem. These symptoms include:

• A fever.
• Unexplained weight loss.
• Blood in your stools.
• Anemia.
• A family history of colon cancer or inflammatory bowel disease.

If you have any of these alarm symptoms, or if your symptoms get worse, your doctor will probably recommend tests.

Your doctor might recommend tests if:

• Your symptoms are getting worse.
• Your symptoms have come on quickly over the past few weeks to months.
• Your symptoms don't match those of most people who have IBS.
• You are older than 50.
• You have blood or pus in your stool.
• You have alarm symptoms, such as unexplained weight loss, fever, or diarrhea at night.
• Your pain wakes you up at night.