Gut flora or, more appropriately, gut microbiota, consists of a complex community of microorganisms that live in the digestive tracts of animals. The gut microbiota comprises the largest and most diverse reservoir of mutualistic microorganisms associated with animals. In this context gut is synonymous with intestinal, and flora with microbiota and microflora. An associated term, sometimes used interchangeably with gut microbiota, is gut microbiome, which refers to the aggregate of all the genomes of gut microbiota.