SIBO Symptoms

The symptoms of SIBO (Small Intestinal Bacterial Overgrowth), also referred to as bacterial overgrowth, cover the full range of digestive complaints as well as many non-digestive complaints.[1] [2] [3] [4] The primary symptoms of SIBO are those of Irritable Bowel Syndrome (IBS): bloating, abdominal pain or discomfort, and diarrhea, constipation or a mixture of both. Symptoms can range in severity from mild to severe. Because SIBO shares the same symptoms as many other diseases, SIBO diagnosis can not be made by symptoms alone. Both symptoms and a positive SIBO test are needed to diagnose SIBO.[5]  For symptom relief treatments, click here.
Typically, SIBO patients have 3-6 symptoms, including at least 1 or 2 of the primary symptoms.
Keynote SIBO Symptoms
  • Bloating
  • Symptoms occur after eating
  • Carbohydrate food sensitivities
Primary SIBO Symptoms
  • Bloating
  • Abdominal Pain/Discomfort
  • Constipation, Diarrhea, or both
Other SIBO Symptoms
  • Belching, Flatulence
  • Heartburn (Acid Reflux/GERD)
  • Nausea or Indigestion
  • Food sits in stomach and won't go down
  • Anxiety
  • Depression (less common than anxiety)
  • Brain Fog
  • Fatigue
Malabsorption Symptoms
  • Steatorrhea (fatty stools)
  • Chronic Low Ferritin or Anemia (Iron or B12)
  • Weight Loss​
SIBO Leaky Gut Symptoms 
  • Food Sensitivities
  • Headaches, Brain symptoms (such as brain fog)
  • Joint Pain
  • Skin symptoms (such as eczema or rashes)
  • Respiratory symptoms (such as nasal mucus or asthma)
  • Mood symptoms (such as depression)

Free ​Guides

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​"Consider SIBO if the symptoms of IBS are present, or if one of the associated conditions along with digestive symptoms, are present." - Dr. Siebecker

SIBO Associated Conditions

Some conditions are strongly associated with SIBO. In addition to the symptoms listed above, if one of these conditions is present and standard treatment for it hasn't helped, SIBO should be considered. (see Associated Diseases listing)  (see Causes of SIBO)
Frequently Associated with SIBO
  • Rheumatoid Arthritis
  • Rosacea and Psoriasis
  • Restless Legs Syndrome
  • Interstitial Cystitis
  • Fibromyalgia
  • Endometriosis
  • Prostatitis (chronic)
  • Ehlers-Danlos Syndrome
  • IBD
  • Celiac
Caused by SIBO
  • IBS
  • Lactose Intolerance
  • Fructose Intolerance (dietary)
  • Histamine Intolerance
  • Mast Cell Activation Syndrome
  • Liver Disease (NASH/NAFLD, Cirrhosis)
  • Gallstone Disease
  • GERD
  • Leaky Gut
  • Anxiety
​"It is mandatory to consider SIBO in all cases of complex non-specific dyspeptic complaints (bloating, abdominal discomfort, diarrhea, abdominal pain), in motility disorders, anatomical abnormalities of the small bowel and in all malassimilation syndromes (malabsorption, maldigestion)." - Bures et. al.
Dr. Siebecker lecturing on Key Indicators of SIBO in 2012.
For more details, please see my article SIBO: Dysbiosis Has a New Name

   Learn more
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