Small Intestinal Bacterial Overgrowth (SIBO)

More than half of the people diagnosed with irritable bowel syndrome (IBS) may have a condition called SIBO.  SIBO stands for Small Intestinal Bacterial Overgrowth and refers to the growth of bacteria in the small intestine.  These bacteria usually originate from the colon and cause problems when they are relocated in the small intestine.  This condition may result in diarrhea, constipation or both and accounts for a large portion of the diagnosis of IBS, for which conventional medicine has had very little treatment to offer.  For both IBS and SIBO, naturopathic medicine has treatment options.  SIBO testing can determine if SIBO is contributing to your IBS.

What causes SIBO?

Many factors can result in SIBO. Some potential causes of SIBO include

  • Gastroenteritis (food poisoning or infectious diarrhea)
  • Certain drug therapies: antibiotics, PPIs (acid blockers), opiates (narcotic pain relievers)
  • Structural abnormalities in the GI tract
  • Post surgery


SIBO Symptoms

SIBO is a disorder of the digestive tract, but the symptoms and conditions that it may cause or impact are myriad and varied. As many as 60% of IBS cases have been shown to relate to SIBO.  This list is a primer of those that are currently identified, but SIBO may be considered when IBS accompanies any chronic, unremitting condition and or in any malabsorption syndrome.

  • Gastrointestinal Symptoms
    How would you characterize your stool?  3-4 on the chart are considered "normal," but frequency and accompanying symptoms should also be considered.
    How would you characterize your stool? 3-4 on the chart are considered “normal,” but frequency and accompanying symptoms should also be considered.
    • Irritable bowel syndrome (IBS)
    • Leaky gut
    • Gas
    • Bloating
    • Abdominal distention after eating
    • Feeling worse after eating
    • Abdominal cramps or pain
    • Diarrhea
    • Constipation
    • Alternating diarrhea and constipation
    • Nausea
    • Heartburn
    • Food allergies or sensitivities
    • Crohn’s disease
    • Ulcerative cholitis
    • Celiac disease
  • Malabsorption Syndromes
    • Weight loss
    • B12 deficiency
    • Iron deficiency
    • Anemia
    • Fatty/Floating stools
  • Associated Conditions
    • Acne rosacea
    • Restless Leg Syndrome
    • Intrastitial cystitis
    • Chronic prostatitis
    • Chronic fatigue syndrome
    • Fibromyalgia
    • Diabetes
    • Cirrhosis of the liver
    • NASH/NAFLD (non alcoholic fatty liver disease)
    • Autoimmune diseases such as
      • Lupus
      • Rheumatoid arthritis
      • Hashimoto’s thyroiditis


SIBO Testing

SIBO is testing by measuring the gases produced by the bacteria living in the gut, specifically hydrogen gas and methane gas.  Gas production is elecited by the prepped patient drinking a lactulose (not lactose) solution which is indigestible to humans and feeds the bacteria.  A transient increase in symptoms is likely with the test, but can be managed after the test with paliative treatment options which will be provided to you.  Testing can be completed at home or at a specific local lab in downtown Portland. If you are an established patient and we’ve recommended SIBO testing, the kit can be mailed directly to your home.

SIBO Treatment Options

The treatment of SIBO by necessity will be multifactorial.  The bacterial population must be reduced while at the same time addressing any causative factors such as structural abnormalities.  Resultant disorders, such as malabsorption, may be addressed concurrently or serially, as apporpriate.  Treatment for SIBO is likely to include some combination of antibiotic therapy, herbal antimicrobial therapy, specific dietary guidelines, specific probiotic guidelines, visceral manipulation and retesting.  A typical treatment round may last for anywhere from 2-6 weeks and treatment may need to be repeated.

If you think you have SIBO and would like to be evaluated by our providers, please call our business office at 503-691-0901.


A New IBS Solution by Dr. Mark Pimentel
Small Intestine Bacterial Overgrowth: Often-Ignored Cause of Irritable Bowel Syndrome by Allison Siebecker, ND, MSOM, LAc, and 
Steven Sandberg-Lewis, ND, DHANP
Small Intestinal Bacterial Overgrowth: The Case of the Perpetual Patient by Allison Siebecker, ND, MSOM, LAc, and Steven Sandberg-Lewis, ND, DHANP
National College of Natural Medicine (NCNM)SIBO Center