**Ligilactobacillus salivarius (formerly Lactobacillus salivarius)** is a lactic acid bacterium (LAB) commonly found in the oropharyngeal-gastrointestinal tract (OGT). It has gained significant attention due to its probiotic and functional properties, including strong resistance and adhesion in the OGT, antioxidant and antimicrobial properties, and the ability to produce bacteriocins. These characteristics make it a promising probiotic for promoting human health. L. salivarius has been shown to positively influence the composition of intestinal microbiota, improving metabolic profiling and maintaining a healthy internal environment. Recent advancements in multi-omics technologies, such as genomics, transcriptomics, proteomics, and metabolomics, have been employed to deepen the understanding of L. salivarius's functional properties and mechanisms. These technologies provide insights into the genetic information, molecular mechanisms, and adaptive responses of L. salivarius to physiological and environmental changes. The review covers the probiotic characteristics of L. salivarius, including its interactions with host microflora and the application of omics approaches. It highlights the strain-specific resistance to acidic pH and bile, adhesion to intestinal mucosa, antioxidant activity, antimicrobial properties, and modulation of the host OGT micro-ecosystem. The review also discusses the use of omics technologies to understand the complex mechanisms behind L. salivarius's functional properties, emphasizing the importance of integrating genomics, transcriptomics, proteomics, and metabolomics for a comprehensive understanding of this probiotic bacterium.**Ligilactobacillus salivarius (formerly Lactobacillus salivarius)** is a lactic acid bacterium (LAB) commonly found in the oropharyngeal-gastrointestinal tract (OGT). It has gained significant attention due to its probiotic and functional properties, including strong resistance and adhesion in the OGT, antioxidant and antimicrobial properties, and the ability to produce bacteriocins. These characteristics make it a promising probiotic for promoting human health. L. salivarius has been shown to positively influence the composition of intestinal microbiota, improving metabolic profiling and maintaining a healthy internal environment. Recent advancements in multi-omics technologies, such as genomics, transcriptomics, proteomics, and metabolomics, have been employed to deepen the understanding of L. salivarius's functional properties and mechanisms. These technologies provide insights into the genetic information, molecular mechanisms, and adaptive responses of L. salivarius to physiological and environmental changes. The review covers the probiotic characteristics of L. salivarius, including its interactions with host microflora and the application of omics approaches. It highlights the strain-specific resistance to acidic pH and bile, adhesion to intestinal mucosa, antioxidant activity, antimicrobial properties, and modulation of the host OGT micro-ecosystem. The review also discusses the use of omics technologies to understand the complex mechanisms behind L. salivarius's functional properties, emphasizing the importance of integrating genomics, transcriptomics, proteomics, and metabolomics for a comprehensive understanding of this probiotic bacterium.