Oral microbiota and gastroenterological diseases

Periodontal diseases are among the most common human ailments. At the beginning of the 21st century, the concept of «periodontal medicine» emerged, examining the relationship between periodontal pathology and other medical conditions. Currently, more than 50 different somatic diseases are associated with periodontal pathology. Periodontal pathology is closely linked to the periodontal microbiota. We searched the Pubmed database for sources published before January 25, 2026, that examined the relationship between periodontal bacteria and the development of gastrointestinal diseases. In this review, we examine the relationship between the periodontal microbiota and two currently relevant gastrointestinal diseases: non-alcoholic fatty liver disease (55 sources) and inflammatory bowel disease (153 sources). The data presented in this review demonstrate that in non-alcoholic fatty liver disease, the leading member of the oral microbiota, Porphyromonas gingivalis, is found directly in liver tissue. Furthermore, a mouth-gut-liver axis is formed, and bacterial translocation of periodontal bacteria into the systemic circulation becomes important. This is accompanied by the circulation of inflammatory mediators and immune complexes, as well as disruption of metabolic, inflammatory, and immunological homeostasis. The oral microbiota is involved in the development and progression of inflammatory bowel diseases through alterations in the intestinal microbiota along the mouth-gut axis, disruption of the intestinal barrier and permeability, release of inflammatory mediators, and impaired immune response. While periodontal diseases can be prevented and controlled, the oral microbiota should be considered a modifiable disease factor. Control of the oral microbiota, particularly its aggressive representatives such as P. gingivalis, should be considered as a potential strategy for the prevention and treatment of diseases associated with periodontal pathology and the periodontal microbiota.