When the Wrong Bacteria Move Into the Wrong Neighborhood
SIBO — small intestinal bacterial overgrowth — is what happens when bacteria that belong in the large intestine migrate up and colonize the small intestine, where they were never meant to live in those numbers. There they ferment your food before you can absorb it, producing the gas, bloating, and distension that define the condition. Dysbiosis, more broadly, is an imbalance in the gut’s microbial community. Neither is a random infection; both are the predictable result of something that stopped keeping the system in order.
This is the GoodMedizen lens. The body is not malfunctioning. It is responding accurately to the information it is being given. Change the inputs and the response begins to change with them.
What SIBO and Dysbiosis Actually Are
SIBO is classified by the gas the overgrowth produces: hydrogen-dominant, often with diarrhea; methane-dominant, now called intestinal methanogen overgrowth and strongly tied to constipation; and hydrogen sulfide, the rotten-egg type. The type matters, because it changes treatment. Dysbiosis is the wider picture — too few beneficial organisms, too many opportunistic ones, or simply too little diversity.
SIBO is also notorious for relapsing, which is the tell that it is downstream of something else rather than a problem in its own right.
What Is Actually Driving It
SIBO is almost never the root; it is the consequence. The drivers we hunt for:
- Impaired motility — the migrating motor complex, the gut’s housekeeping wave that sweeps bacteria downstream between meals, often stalled after food poisoning or by stress
- Low stomach acid, which normally sterilizes incoming food
- Sluggish bile and pancreatic enzymes
- A prior bout of food poisoning, since post-infectious SIBO is a well-defined cause
- Structural issues, adhesions, or a sluggish ileocecal valve
- Chronic stress, which suppresses the housekeeping wave directly
- An underactive thyroid, which slows the whole system
Why It Gets Missed or Mistreated
SIBO is frequently misread as plain IBS and managed with symptom control, or it is treated once and declared solved when the overgrowth returns months later, because the driver behind it was never addressed.
Signs and Patterns
- Bloating and distension, often worsening through the day or after meals
- Excess gas
- Abdominal discomfort or pain
- Diarrhea, constipation, or an alternating pattern
- Reactions to carbohydrates and fiber in particular
- Nutrient deficiencies such as B12 and iron from malabsorption
- Brain fog and fatigue
How We Look at It — The Testing
- Breath testing — a lactulose breath test measuring hydrogen and methane across about three hours, the standard way to identify an overgrowth and its gas type
- The broader gut — GI-MAP through Diagnostic Solutions, to map the microbiome, opportunists, markers of digestion and inflammation, and intestinal permeability
- Thyroid — a full panel with antibodies, since an underactive thyroid slows motility, and we often see symptoms at a TSH as low as 1.75
- Nutrient consequences — B12 with homocysteine and MMA, a complete iron and ferritin profile, 25-OH vitamin D, and RBC magnesium, since overgrowth interferes with absorption
- Foundational — a comprehensive metabolic panel with GGT and a CBC with differential
Broad baseline labs do not have to be expensive. Services such as Function Health let patients obtain large workups affordably, and we have no financial stake in that — we would rather your budget go toward care than toward lab markups. For targeted functional testing we order through Diagnostic Solutions (GI-MAP) for the microbiome, Quicksilver Scientific for heavy metals, and through Fullscript where it serves you best, with every marker read against optimal ranges rather than the wide line between “normal” and “abnormal.”
The Chinese Medicine Lens
Chinese medicine centers digestion on the Spleen and Stomach, the systems responsible for transforming food into usable qi and blood. SIBO and dysbiosis read most often as Spleen qi deficiency with accumulated dampness — a digestion too weak to transform what it is given, so food stalls and ferments, generating the damp, bloated, heavy quality patients describe. Where there is burning or urgency, damp-heat has developed; where stress drives it, Liver qi is overacting on an already weakened Spleen.
Treatment strengthens the Spleen so it can transform food again, clears the accumulated damp, and settles the stress pattern that so often sits on top.
How Acupuncture and Functional Medicine Help
Acupuncture supports motility, calms the stress state that stalls the housekeeping wave, and strengthens the digestive function that lets the gut defend itself.
The functional work is sequenced deliberately: address the overgrowth, then restore motility with the migrating motor complex in mind, support stomach acid, bile, and enzymes upstream, and rebuild a diverse microbiome — all while opening the exits first so the body can clear what is being stirred up. This is squarely the GoodMedizen pathway.
Care That Works With Your Other Providers
Where structural causes or red-flag symptoms are present, evaluation by a gastroenterologist comes first, and we coordinate alongside it.
Your Body Isn’t Broken
If you have spent years being told your labs look normal while you clearly do not feel normal, you have not been imagining it. With SIBO, clearing the overgrowth is only half the work; the lasting part is restoring what let it take hold. Your body is not broken. The support has just been missing.
At GoodMedizen in downtown Seattle, we treat the system driving the condition, not only the symptoms it produces.