Levilactobacillus brevis

Lactobacillus brevis · L. brevis

Snapshot

Indications	Contraindications
Gingival bleeding^{1, 2} Dental plaque¹ Oral mucositis prevention³ Bacterial vaginosis⁴ Influenza incidence in children⁵ Academic stress⁶ Recurrent genital herpes⁷	Milk allergy⁸ Pregnancy or nursing⁸

Levilactobacillus brevis (formerly Lactobacillus brevis) is a lactic acid bacterium found in fermented foods such as kimchi. As a probiotic it is thought to act by modulating oral microbial communities and local inflammatory signaling.¹ People use it mainly for oral health, including gingival bleeding and mucositis during cancer treatment. Other uses are vaginal health, influenza prevention in children, and stress.

Oral mucositis evidence is split: a randomized trial in head and neck cancer found less severe mucositis with one strain's lozenges, while a later multicentre trial found no difference. As a periodontitis adjunct, one trial found less gingival bleeding but more persisting deep sites. A 2025 mini review of non-pharmacological options for estrogen decline reported that a probiotic maintained circulating estrogens in peri- and postmenopausal women over 12 weeks, while levels fell on placebo⁹. There are 77 products listing Levilactobacillus brevis, mostly capsules, while the oral trials used lozenges; see Form comparison.

Effects are strain-specific, so results for one strain do not transfer to another.⁸ United States product labels warn against use in pregnancy or nursing on 2 of 30 labels, and most others ask for a healthcare professional's advice first⁸.

Last updated October 17, 2026. Read how we make monographs.

In the full monograph

41 sources, 36 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources