Abstract
Oral cavity and gut are important parts of the human digestive tract. The structure and pathogenesis of oral and gut microbial communities have been extensively investigated. The interaction and pathogenic effects of oral and gut microbiota have also been widely explored. This review aimed to integrate data from literature and discuss the structures and functions of microbial communities in the oral cavity and gut. The mutual colonization and pathogenesis of oral and gut microbes and the relationship between these phenomena and involved systemic diseases are also described.