SIBO Symptoms Checklist: How to Tell If Small Intestinal Bacterial Overgrowth Is Your Issue

What Is SIBO?

Small Intestinal Bacterial Overgrowth occurs when excess or misplaced bacteria populate the small bowel, fermenting carbohydrates, producing gas (hydrogen/methane/hydrogen sulfide), and disrupting digestion, absorption, and motility. SIBO is common in IBS, hypothyroidism, post-infectious IBS, motility disorders, adhesions, and after proton pump inhibitor overuse.

Core Symptom Checklist

• Bloating/distension 1–3 hours after meals (post-prandial ballooning)
• Excess gas, belching, abdominal pressure
• Altered stools:
  • Methane-dominant: constipation, incomplete evacuation
  • Hydrogen-dominant: loose stools/diarrhea
  • H2S-associated: foul gas, urgency, variable stools
• Upper GI discomfort: early fullness, nausea, reflux-like symptoms
• Food reactivity: worse with onions/garlic/beans/wheat/dairy/sugar alcohols
• Extraintestinal: brain fog, fatigue, joint/skin flares, nutrient deficiencies (B12, iron), unintended weight changes
• History clues: food poisoning, frequent antibiotics, chronic stress, PPIs, abdominal surgery/adhesions, EDS/hypermobility, hypothyroidism, diabetes, SSc, slow motility, endometriosis.

Self-Screen Triggers

• Symptoms improve on low-FODMAP or low-fermentation diet but rebound when liberalizing carbs.
• Constipation improves with methane-targeted strategies (e.g., certain antibiotics/herbals).
• Recurring symptoms after antibiotics.

How SIBO Is Tested

• Breath testing (lactulose or glucose): Measures rises in hydrogen/methane over time; methane ≥10 ppm at any point suggests intestinal methanogen overgrowth (IMO).
• Labs to consider: B12, iron/ferritin, folate, vitamin D; celiac panel; thyroid function.
• Imaging/endoscopy: if alarm features or to evaluate structural/motility issues.

Treatment Pillars (Clinician-Guided)

• Antimicrobials:
  • Antibiotics (e.g., rifaximin for hydrogen; rifaximin+neomycin/metronidazole for methane) or evidence-based herbal protocols (e.g., berberine, oregano oil, allicin for methane).
• Diet:
  • Low-FODMAP/low-fermentation during treatment; avoid being overly restrictive long-term; strategic reintroduction for diversity once symptoms calm.
• Motility support:
  • Meal spacing (4–5 hours between meals, 12-hour overnight fast) to leverage migrating motor complex.
  • Prokinetics post-treatment (e.g., low-dose erythromycin, prucalopride, or botanicals) when indicated.
• Relapse prevention:
  • Treat root causes (adhesions, hypothyroidism, PPI overuse, dysglycemia, constipation).
  • Manage stress/sleep; regular movement; address oral/nasal dysbiosis if relevant.

At-Home Symptom Soothers

• Gentle meals: protein + low-FODMAP veggies + tolerated starch (e.g., jasmine rice, potatoes), cooked/peeled produce early on.
• “Low and slow” fiber: psyllium/PHGG in constipation-predominant; avoid high-fermenters during flares.
• Breathwork: 5–10 minutes post-meal diaphragmatic breathing; light walking after meals.

When to Seek Care Promptly

• Weight loss, anemia, bleeding, persistent fever, severe pain, or nocturnal symptoms.