Small Bowel Bacterial Overgrowth

A healthy small intestine maintains a constant balance of bacteria to ensure normal digestive functioning.

The following can alter the bowel’s environment, reducing the number of protective bacteria:

  • Exposure to antibiotics
  • Decreased stomach acid secretion
  • Diminished digestive enzyme production
  • Gastrointestinal obstructions
  • Radiation therapy
  • Motility disorders

When the number of protective bacteria is compromised, it upsets a balance. Some harmful bacteria normally kept in check by the protective bacteria are allowed to grow without restraint. This leads to a condition known as Small Bowel Bacterial Overgrowth (SBBO). If left untreated, the condition can lead to nutrient malabsorption with malnutrition.


Symptoms of SBBO include bloating, gas, diarrhea and abdominal pain.

Risk Factors

The elderly are at an increased risk of developing SBBO due to decreased incidence in gastric acid production and increased occurrence of small bowel diverticula. Patients who have undergone surgery altering the stomach and beginning of the small bowel also are at risk for developing this condition.


A simple non-invasive breath test can determine if you suffer from SBBO.


Treatment of SBBO is aimed at restoring normal gut flora with proper antibiotic therapy, which should lead to a decrease in symptoms and improvement in nutritional health.

In a few individuals, surgical treatment can be used to correct the structural abnormality that leads to SBBO. However, under most circumstances, structural abnormalities that lead to SBBO, like out-pouchings of the small bowel, are not a curable condition and requires ongoing monitoring with therapy.