Firmicutes/Bacteroidetes Ratio

The Firmicutes/Bacteroidetes ratio is a rough indicator of bacterial shifts.  The following are not included in these gtoups: BifidiobactiumEscherichia coli

Firmicutes: Includes Lactobacillus, Enterococcaceae, Bacillus. Usually Gram-Positive


Bacteroidetes usually gram-negative


Not in either of the above: BifidiobactiumEscherichia coli

When the ratio increases then either

  • More firmicutes
  • Less bacteroidetes
  • or both with firmicutes increasing faster.

When the ratio decreases then either

  • Less firmicutes
  • More bacteroidetes
  • or both with firmicutes decreasing faster.

Lower Ratio

  • Systemic lupus erythematosus [2017]
  • Coeliac disease [2016]
  • Crohn’s Disease [2016]
  • Aging [2014]

Higher Ratio

  • Obese (higher BMI) [2017]
  • Gut dysbiosis in hypertension [2017] [2017]
  • Autism spectrum disorders [2017]
  • Chronic Fatigue Syndrome [2013]
  • Gulf War Illness [2017]
  • Irritable bowel syndrome [2016] [2016] 3x higher
  • Sjögren’s syndrome [2007]
  • Rheumatoid Arthritis  [2014] ” The signs of III degree dysbiosis, by reducing the concentration of Bacteroides spp., Bifidobacterium spp., Lactobacillus spp. populations, typical strain E. coli. But over growth of populations Klebsiella spp., Proteus spp., Staphylococcus spp., atypical forms of E. coli, Candida spp. ” Almost the identical pattern reported for CFS in 1998.

Observed in Samples

About 91% have ratios (you need values of both to get a ratio). We see a major rapid increase in the ratio with those in the highest ratio.


I will add more to this page in the future.

  • Increases
    • capsaicin [2016]
    • Dairy products [2016]
    • Proton pump inhibitor [2016] “we discovered a decrease in Bacteroidetes and an increase in Firmicutes “
  • Decreases –
    • Resveratrol [2014]
    • Lactobacillus Fermentum [2017]
    • Pea Fibre [2017]
    • Melatonin [2017]
    • Cranberry [2017]