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Chronic fatigue syndrome

Compared within 3 studies that had both: 302 people with chronic fatigue syndrome and 233 healthy people. 103 microbes are less common in people with chronic fatigue syndrome, and 35 more common.

A difference is an association: it doesn’t mean these microbes cause, prevent or treat chronic fatigue syndrome.

Phylum

Searching opens both lists and shows only matching rows.

Less common in chronic fatigue syndrome · 103

Strongest first, then the biggest gap · Each figure is 10 people Strongest first · Each figure is 10 people
  1. Clostridium sp. AF20-17LB in 3 studies Healthy 66% chronic fatigue syndrome 32%
  2. Clostridiaceae bacterium AF18-31LB in 3 studies Healthy 80% chronic fatigue syndrome 49%
  3. Clostridium fessum in 3 studies Healthy 86% chronic fatigue syndrome 57%
  4. Coprococcus catus in 3 studies Healthy 70% chronic fatigue syndrome 39%
  5. Anaerobutyricum hallii in 3 studies Healthy 79% chronic fatigue syndrome 52%

More common in chronic fatigue syndrome · 35

Strongest first, then the biggest gap · Each figure is 10 people Strongest first · Each figure is 10 people
  1. Blautia caecimuris in 3 studies Healthy 21% chronic fatigue syndrome 47%
  2. [Clostridium] symbiosum in 3 studies Healthy 24% chronic fatigue syndrome 50%
  3. Enterocloster clostridioformis in 3 studies Healthy 9.8% chronic fatigue syndrome 30%
  4. Thomasclavelia ramosa in 3 studies Healthy 9.8% chronic fatigue syndrome 30%
  5. Enterocloster bolteae in 3 studies Healthy 43% chronic fatigue syndrome 67%

As many carry these · 5 the amount differs

Strongest first, then the biggest gap · Each figure is 10 people Strongest first · Each figure is 10 people
  1. Ruthenibacterium lactatiformans in 3 studies Healthy 84% chronic fatigue syndrome 89%

    Carriers have about twice as much, in 3 of 3 studies (0.03% → 0.08% of their gut microbes).

  2. Dysosmobacter welbionis in 3 studies Healthy 97% chronic fatigue syndrome 97%

    Carriers have about twice as much, in 3 of 3 studies (0.23% → 0.46% of their gut microbes).

  3. Clostridiales bacterium in 3 studies Healthy 90% chronic fatigue syndrome 87%

    Carriers have about twice as much, in 3 of 3 studies (0.10% → 0.23% of their gut microbes).

Where these numbers come from

Studies
Only GMrepo projects that had people with the condition and healthy people, 10 or more of each. Numbers come from those studies, never from pooling.Sampled in the United States.
How common
The share of people whose sample has any of it, in the people with the condition and in the healthy people of those same studies. Tested within studies (Cochran–Mantel–Haenszel, corrected for testing many microbes); a difference counts when it is clear and meaningful (Cohen’s h of 0.2 or more).
Strength word
Counted by code from how many studies point the same way: Seen again and again (3 or more, none clearly the other way), Seen more than once (2, the majority), Seen once (1, listed last). Where studies disagree, a row isn’t listed.
Each study
Tap a row for every study’s own numbers, and for how much carriers have.
Analysis
Our analysis of GMrepo data. GMrepo on Data sources · Read the rules

Also compared · 294 microbes

Compared within studies that had both, but not listed above.

No meaningful difference · 294
PubMed · human studies and reviews first

Recent research

All research on it
  1. Review International journal of molecular sciences · 2025
    The Gut-Brain-Immune Axis in Environmental Sensitivity Illnesses: Microbiome-Centered Narrative Review of Fibromyalgia Syndrome, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, and Multiple Chemical Sensitivity.
    PubMed ↗
  2. Review Neurogastroenterology and motility · 2023
    Intestinal bacteria associated with irritable bowel syndrome and chronic fatigue.
    PubMed ↗
  3. Cell host & microbe · 2023
    Deficient butyrate-producing capacity in the gut microbiome is associated with bacterial network disturbances and fatigue symptoms in ME/CFS.
    PubMed ↗
  4. Systematic review Beneficial microbes · 2018
    Are probiotic treatments useful on fibromyalgia syndrome or chronic fatigue syndrome patients? A systematic review.
    PubMed ↗
  5. Microbiome · 2017
    Fecal metagenomic profiles in subgroups of patients with myalgic encephalomyelitis/chronic fatigue syndrome.
    PubMed ↗

Source: PubMed, U.S. National Library of Medicine · 5 linked papers, last 10 years