Symptoms and Signs of SIBO (Small Intestinal Bacterial Overgrowth)

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Medically Reviewed on 3/12/2022

Doctor's Notes on SIBO (Small Intestinal Bacterial Overgrowth)

SIBO (small intestinal bacterial overgrowth) signs and symptoms include

Some patients have chronic constipation, body aches, and/or fatigue. Some patients appear to be malnourished.

Abnormally large populations of bacteria digesting food in the intestine produce enough gas so that it can accumulate in the abdomen and cause SIBO disease. These bacteria also convert foods like sugars and carbohydrates in large amounts that are irritating or toxic to cells of the intestinal tract. At the same time, they compete with the patient for food. Partial or intermittent obstruction of the small intestine can encourage the growth of these bacteria. Other conditions such as neurologic and muscular diseases that slow the gastrointestinal motility so that bacterial overgrowth is not swept away. Diverticuli (pouches in the GI small intestine mucosa) allow large bacterial populations to thrive as the populations are not swept away even with normal GI motility.

What Are the Treatments for SIBO?

Treatments for SIBO are, in general, simple. Antibiotics are prescribed to reduce and stabilize the gut bacteria and diet changes that may promote a reduced population of gut bacteria. Treatments may include the following:

  • Broad spectrum antibiotics like rifaximin, amoxicillin/clavulanate, or metronidazole plus cephalexin
  • Diet changes (reduce intake of following)
    • Oligosaccharides like wheat, legumes
    • Disaccharides like lactose, butter
    • Monosaccharides like glucose, fruits, and honey
    • Fruits with pits like cherries, peaches
  • Elemental liquid diet (Caution: needs a doctor's supervision)

You and your doctor can discuss the optimal treatment plan for your SIBO.

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Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.