Bacterial overgrowth syndrome is a condition associated with an increased number and/or type of bacteria in the upper gastrointestinal tract.

Small bowel bacterial overgrowth may result from structural abnormalities such as diverticula (out-pouchings) or strictures (narrowing), abnormal motility, or motor function from diseases such as diabetes, scleroderma, or Crohn’s Disease, or from prior gastrointestinal surgery.


Affected patients may have one or more symptoms including bloating, abdominal discomfort, watery diarrhea, and weight loss.

Damage to the small intestine may occur and interfere with absorption of nutrients and vitamins.


The diagnosis is made by breath testing or by culturing bacteria from the small intestine.


Treatment includes eliminating any condition which may predispose the patient to bacterial overgrowth and antibiotics to reduce the number of bacteria.