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Streptococcus

A diverse genus spanning protective and cavity-causing species · facultative · Lives in saliva

The short version

Streptococcus is the most abundant bacterial genus in your mouth — about 1 in 3 of your oral bacteria. Some species in the genus protect oral health (S. salivarius, S. sanguinis); others cause cavities (S. mutans). Your panel reports the species individually — check the species-level rows for the most useful read.

Do

Reduce free sugars (especially sucrose) and increase dietary fiber. Three months of higher fiber and less sugar shifts the Streptococcus community toward the protective species.

Avoid

Prolonged grazing on fermentable carbohydrates and daily antiseptic mouthwash. Both encourage cavity-causing species and disrupt the broader oral community.

Species pages

Deeper writeups for individual species in this genus.

Streptococcus mutans
The classic cavity-causing bacterium
Streptococcus salivarius
A dominant healthy oral commensal and the basis of the K12 probiotic
Streptococcus sanguinis
A health-associated early colonizer that antagonizes Streptococcus mutans

Synthesized from 13 peer-reviewed sources · Last updated May 2026

This information is for wellness purposes only and is not a medical assessment. Always consult a medical professional about any health concerns.

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