• Gas
  • Bloating
  • Pain
  • Mucous in stools
  • Foul-smelling gas and stools
  • Diarrhea.

A toxic metabolic substance produced by the bacteria injures intestinal cells and impairs absorption, resulting in nutrient deficiencies, food allergies and intolerances, and poorly functioning digestive enzymes.

What Causes Bacterial Overgrowth?

Decreased motility in the small intestine

Caused by excess dietary sugar, chronic stress, and conditions such as diabetes, hypothyroidism, and scleroderma. In the United States, up to 40% of chronic diarrhea in people with diabetes is associated with bacterial overgrowth.


As people get older, the amount of stomach acid they secrete declines. Stomach acid is acidic and helps to kill bacteria in the small intestine if there is less stomach acid, bacteria are more likely to proliferate. Another very common cause of hypochlorhydria is excessive use of antacids.

Structural abnormalities in the small intestine

Gastric bypass surgery, small intestinal diverticula, blind loop, intestinal obstruction, and Crohn’s disease fistula are some of the structural causes of bacterial overgrowth.

Other causes include:

  • Immune deficiency
  • Stress
  • Certain medications such as steroids, antibiotics, and birth control pills
  • Inadequate dietary fiber
  • Pancreatic enzyme deficiency

All of these things can cause bacterial overgrowth


  • Abdominal bloating and gas after meals
  • Pain
  • Constipation
  • Chronic loose stools or diarrhea – studies have found 48-67% of people with chronic diarrhea had bacterial overgrowth.
  • Soft, foul-smelling stools that stick to the bowl
  • Fatigue – megaloblastic anemia due to vitamin B12 malabsorption
  • Depression
  • Nutritional deficiency despite taking supplements
  • Weight loss
  • Abdominal pain
  • Mucous in stools
  • Bloating worse with carbs, fiber, and sugar

Getting A Diagnosis

The “gold standard” test is to take bacterial cultures of small intestine fluid.

  • Lactulose hydrogen breath test – The most common test is the lactulose hydrogen breath test because it is less invasive. Lactulose is a non-absorbable sugar that’s fermented if there are intestinal bacteria, resulting in hydrogen production. If there is bacterial overgrowth, fasting hydrogen levels will be high. In addition, after ingesting glucose, there will be a significant rise in hydrogen.
  • Other tests are the Schilling test (for b12 deficiency). A small bowel-follow may be done to look for structural problems.
  • One of the underlying causes of bacterial overgrowth is insufficient stomach acid, called hypochlorhydria. Stomach acid naturally declines with age. Take the hypochlorhydria screening test.

What Conditions Can Bacterial Overgrowth Lead To?


It can be difficult to get proper testing and treatment for bacterial overgrowth because some doctors don’t understand this condition. The conventional treatment for bacterial overgrowth is antimicrobial drugs.


The most studied natural treatment for bacterial overgrowth is enteric coated peppermint oil, which is peppermint oil that has an edible, hard shell around it so that the capsule doesn’t open until it is in the small intestine. It kills bacteria in the small intestine.

Other Herbal Treatment Options


During treatment, it is necessary to limit the intake of sweet and starchy foods. People usually experience a noticeable decline in bloating, gas, indigestion, diarrhea, and other digestive symptoms.

Medium Chain Triglycerides

Unlike regular oils, which a person with bacterial overgrowth may not be able to assimilate, medium chain triglycerides are absorbed directly without the need for digestive enzymes. Medium chain triglycerides are often recommended for people with bacterial overgrowth or any type of malabsorption. Coconut oil is a medium chain triglyceride.

Digestive Enzymes

  • Digestive enzyme supplements can support the body’s digestive enzymes until the function is restored. They should be taken before meals. A typical dose is one capsule before each meal.
  • Vitamins and minerals that may be deficient in people with bacterial overgrowth include vitamin B12, magnesium, calcium, iron, zinc, copper, vitamin A, D, E, and K.
  • Probiotics – needed to replace healthy bacteria in the intestines. Lactobacillus Plantarum and Lactobacillus GG are some types that have been used for bacterial overgrowth.