Pediococcus acidilactici is a lactic acid bacterium commonly used as a probiotic in both human and animal nutrition. Several peer-reviewed studies have investigated its effects on gut health, particularly its ability to support and maintain the balance of the microbial community in the large intestine (colon). Scientific evidence suggests that P. acidilactici can survive gastric transit and colonize the colon, where it may inhibit pathogenic bacteria via competitive exclusion and the production of antimicrobial substances (such as bacteriocins). Additionally, this bacterium can enhance the production of short-chain fatty acids (SCFAs), such as acetate and butyrate, which are beneficial for colonocyte health and maintaining gut barrier function.

Animal studies and a limited number of human clinical trials have shown that P. acidilactici supplementation can reduce symptoms of gastrointestinal discomfort, such as diarrhea and constipation, and may help restore microbiota balance after antibiotic use. However, most of the available evidence is preclinical or based on small-scale human studies; large, well-designed clinical trials are still needed to confirm and clarify its effects in humans. Thus, while the scientific rationale for using P. acidilactici to support large intestine health is plausible and supported by early evidence, it is not yet definitive or universally accepted.