Bring your medical records, especially if you have had surgery on your stomach or intestines, have any known bowel condition, or have received radiation to the abdomen or pelvis.

Write down your symptoms, including when they started and how they may have changed or worsened over time.

Here's some information to help you get ready for your appointment, and what to expect from your doctor. After an initial evaluation, you may be referred to a doctor who specializes in treatment of digestive disorders (gastroenterologist). If you have signs and symptoms that are common to small intestinal bacterial overgrowth (SIBO), make an appointment with your doctor. Request an Appointment at Mayo Clinic Preparing for your appointment Some affected people may tolerate yogurt because the bacteria used in the culturing process naturally break down lactose. In that case, it's important to avoid most lactose-containing products, or use lactase preparations that help digest milk sugar. Damage to the small intestine may cause you to lose the ability to digest milk sugar (lactose). People with SIBO may need intramuscular injections of vitamin B-12, as well as oral vitamins, calcium and iron supplements. These treatments may improve vitamin deficiencies, reduce intestinal distress and help with weight gain: Malnutrition can be treated, but the damage it causes can't always be reversed. Nutritional supportД¬orrecting nutritional deficiencies is a crucial part of treating SIBO, particularly in people with severe weight loss. Switching among different drugs can help avoid this problem. As a result, antibiotics can cause some of the very problems they're trying to cure, including diarrhea. Antibiotics wipe out most intestinal bacteria, both normal and abnormal. Some people with a loop in their small intestine may go for long periods without needing antibiotics, while others may need them regularly.Дoctors may also switch among different antibiotics to help prevent bacterial resistance. But bacteria can return when the antibiotic is discontinued, so treatment may need to be long term. Testing may be performed if antibiotic treatment is not effective.ДЄ short course of antibiotics often significantly reduces the number of abnormal bacteria. Doctors may start this treatment if your symptoms and medical history strongly suggest this is the cause, even when test results are inconclusive or without any testing at all. Antibiotic therapyДЇor most people, the initial way to treat bacterial overgrowth is with antibiotics. In that case, treatment focuses on correcting nutritional deficiencies and eliminating bacterial overgrowth.

Whenever possible, doctors treat SIBO by dealing with the underlying problem - for example, by surgically repairing a postoperative loop, stricture or fistula. In some cases, your doctor may recommend imaging tests, such as X-rays, computerized tomography (CT) scanning or magnetic resonance imaging (MRI) to look for structural abnormalities of the intestine. In addition to these tests, your doctor may recommend blood testing to look for vitamin deficiency or a stool evaluation to test for fat malabsorption. A sample of intestinal fluid is withdrawn and then tested in a laboratory for the growth of bacteria. To obtain the fluid sample, doctors pass a long, flexible tube (endoscope) down your throat and through your upper digestive tract to your small intestine. This is currently the gold standard test for bacterial overgrowth.

Small intestine aspirate and fluid culture.

Although widely available, breath testing is less specific than other types of tests for diagnosing bacterial overgrowth. A rapid rise in exhaled hydrogen or methane may indicate bacterial overgrowth in your small intestine.

This type of noninvasive test measures the amount of hydrogen or methane that you breathe out after drinking a mixture of glucose and water.

In order to diagnose small intestinal bacterial overgrowth (SIBO), you may have tests to check for bacterial overgrowth in your small intestine, poor fat absorption, or other problems that may be causing or contributing to your symptoms.

Bacterial overgrowth treatment