SIBO (Small Intestinal Bacterial Overgrowth)
Excess bacteria in the small intestine causing bloating, pain, and malabsorption.
Overview
SIBO occurs when there's an abnormal increase in bacteria in the small intestine, which normally has relatively few bacteria compared to the large intestine. These bacteria ferment food in the small intestine, producing gas and causing bloating, pain, diarrhea, and malabsorption of nutrients. SIBO is a common but underdiagnosed cause of IBS-like symptoms and is associated with chronic fatigue, likely due to nutrient deficiencies and inflammation.
Common Age
Adults of any age; more common over 60
Prevalence
Up to 15% of healthy people; much higher in IBS patients
Duration
Treatable but often recurs; addressing root cause is key
Common Symptoms
- Bloating (often severe, worse after eating)
- Abdominal pain or discomfort
- Gas and flatulence
- Diarrhea (or sometimes constipation)
- Nausea
- Fatigue and weakness
- Brain fog
- Vitamin deficiencies (B12, iron, fat-soluble vitamins)
- Unintentional weight loss
- Food intolerances
- Joint pain
- Skin problems (rosacea, acne)
Possible Causes
- Reduced gut motility
- Low stomach acid (from PPIs, aging)
- Structural abnormalities (strictures, adhesions)
- IBS (especially constipation-predominant)
- Diabetes (affects gut nerves)
- Hypothyroidism
- Celiac disease
- Crohn's disease
- Prior abdominal surgery
- Medications (opioids, PPIs)
- Immune deficiency
Note: These are potential causes. A healthcare provider can help determine the specific cause in your case.
Quick Self-Care Tips
- 1Get properly tested (breath test)
- 2Work with knowledgeable practitioner
- 3Consider dietary changes (low FODMAP)
- 4Address underlying cause
- 5Complete full antibiotic course
- 6Space meals (avoid constant snacking)
- 7Prokinetics may help prevent recurrence
- 8Test for nutrient deficiencies
Disclaimer: These are general wellness suggestions, not medical treatment recommendations. They may help manage symptoms but should not replace professional medical care.
Detailed Treatment & Solutions
1DIAGNOSIS
Lactulose or glucose breath test measures hydrogen and methane. Elevated levels suggest SIBO. Some prefer small intestine aspirate (more invasive but gold standard).
2ANTIBIOTICS
Rifaximin is first-line (targets gut, minimal absorption). Neomycin often added for methane-dominant SIBO. Alternative: herbal antimicrobials (may be equally effective).
3DIETARY MANAGEMENT
Low FODMAP diet reduces fermentable substrates. Elemental diet (complete nutrition in absorbable form) can work for resistant cases. Long-term, identify and avoid personal triggers.
4ADDRESS ROOT CAUSE
Prokinetics help if motility is slow. Treat underlying conditions (hypothyroidism, diabetes). Review medications. Address structural issues if present.
5PREVENT RECURRENCE
SIBO often recurs. Prokinetics at bedtime (low-dose erythromycin or herbal). Meal spacing (4-5 hours between meals). Avoid PPIs if possible.
6REPAIR AND RESTORE
After treatment, repair gut lining. Address nutrient deficiencies. Gradual reintroduction of foods. Probiotics are controversial—some help, some worsen.
Important: Always consult a healthcare professional before starting any treatment regimen. The solutions above are for educational purposes and may not be suitable for everyone.
Risk Factors
- IBS
- Diabetes
- Low stomach acid
- Prior surgery
- Slow motility
- PPI use
Prevention
- Address gut motility
- Avoid unnecessary PPIs
- Treat underlying conditions
When to See a Doctor
Consult a healthcare provider if you experience any of the following:
- Chronic bloating and digestive symptoms
- Symptoms of IBS not responding to treatment
- Signs of malnutrition or vitamin deficiency
- Unexplained fatigue with digestive symptoms
- Weight loss without trying
Talk to a Healthcare Provider
If your symptoms are persistent, severe, or concerning, please consult with a qualified healthcare professional for proper evaluation and personalized advice.
Frequently Asked Questions
QWhat's the difference between hydrogen and methane SIBO?
Hydrogen-dominant SIBO typically causes diarrhea, while methane-dominant (also called IMO—intestinal methanogen overgrowth) typically causes constipation. Methane slows gut motility. Treatment may differ—methane often needs additional antibiotics like neomycin. Breath testing identifies which type you have.
QWhy does SIBO keep coming back?
SIBO recurs in up to 50% of people because the underlying cause (slow motility, structural issues, etc.) often persists. Prevention requires addressing root cause, possibly using prokinetics, spacing meals properly, and sometimes periodic antimicrobial treatment. Work with a practitioner to find your recurrence triggers.
Related Conditions
Chronic Fatigue
Persistent tiredness that doesn't improve with rest and affects daily activities.
Hypothyroidism (Underactive Thyroid)
A condition where the thyroid gland doesn't produce enough hormones.
Irritable Bowel Syndrome (IBS)
A common disorder affecting the large intestine, causing cramping, abdominal pain, bloating, gas, and diarrhea or constipation.
Hypothyroidism (Underactive Thyroid)
A condition where the thyroid gland doesn't produce enough thyroid hormone.
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Medical Disclaimer
The information on this page is for educational purposes only and is not intended as medical advice. It should not be used for self-diagnosis or self-treatment. Always seek the guidance of a qualified healthcare professional with any questions you have regarding a medical condition. If you are experiencing a medical emergency, call your local emergency services immediately.
Information last reviewed: January 2026
This page provides educational information only. It is not medical advice.