Limited evidenceGut health

Lactobacillus Salivarius

A species native to the mouth and gut. Its small trial base is mostly dental — bad breath and periodontal measures — rather than digestive.

Evidence last reviewed: August 2026

What the science says

Oral malodor Limited evidence
A double-blind, randomized, placebo-controlled crossover trial of L. salivarius WB21 tablets reported reduced oral malodor parameters. Small, single-center and short.
Periodontal health Limited evidence
A double-blinded, placebo-controlled randomized trial of Lactobacillus as an adjunct in severe periodontitis reported improvement in clinical measures and halitosis, and a small study of the SGL03 strain found changes in periodontal and microbiological parameters. Both are adjuncts to dental treatment, not replacements.
Gut symptoms Limited evidence
Despite being sold as a gut probiotic, L. salivarius has no adequately sized randomized trial for IBS, constipation or bloating on its own.

Dosage & safety

Studied doseOral trials used lozenges or tablets delivering roughly 1–6 billion CFU per day, dissolved in the mouth. Capsule doses for gut use are label-based rather than trial-based.

SafetyWell tolerated. For oral use, prefer sugar-free lozenges. Standard caution for live probiotics in severe immunosuppression, endocarditis risk or with central lines.

Scientific references

Lactobacillus salivarius WB21--containing tablets for the treatment of oral malodor: a double-blind, randomized, placebo-controlled crossover trial
Suzuki N, Yoneda M, Tanabe K, Fujimoto A, Iha K, Seno K, Yamada K, Iwamoto T, Masuo Y, Hirofuji T — Oral Surg Oral Med Oral Pathol Oral Radiol, 2014
Clinical effect of Lactobacillus on the treatment of severe periodontitis and halitosis: A double-blinded, placebo-controlled, randomized clinical trial
Soares LG, Carvalho EB, Tinoco EMB — Am J Dent, 2019
The Effect of Lactobacillus salivarius SGL03 on Clinical and Microbiological Parameters in Periodontal Patients
NĘdzi-GÓra M, WrÓblewska M, GÓrska R — Pol J Microbiol, 2020

Where to buy

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