Lactobacillus salivarius is a well-studied probiotic bacterium naturally found in the human gastrointestinal tract, oral cavity, and other mucosal surfaces. Scientific evidence suggests that L. salivarius can support the health of mucus membranes—specifically by modulating the microbial balance and enhancing barrier function in areas such as the oral cavity, gut, and urogenital tract. Several studies have demonstrated that L. salivarius can inhibit pathogenic bacteria and reduce inflammation on mucosal surfaces. For example, clinical trials and in vitro studies report that L. salivarius can help reduce the incidence of dental caries, periodontitis, and oral candida due to its ability to compete with or suppress pathogenic microbes in the oral mucosa. Additionally, some research suggests it may help alleviate symptoms of irritable bowel syndrome (IBS) and other gastrointestinal conditions by supporting the intestinal mucosal barrier and modulating immune responses.

However, while the evidence is promising, it is not yet robust or comprehensive enough to warrant a higher rating. Most studies are small, short-term, or focused on specific populations. The mechanism by which L. salivarius supports mucus membranes is thought to be related to the production of bacteriocins, improvement of epithelial integrity, and modulation of local immune responses. Overall, there is scientific basis for its use, but more large-scale, high-quality clinical trials are needed to fully validate these effects.