The microbiome and microbiota are terms often used interchangeably to refer to microbial communities throughout the body, with the highest density in the distal gut and colon.

“I think, just to start off with clarifying terminology, microbiome and microbiota quite often are referred to, or used to refer to our microbial community interchangeably, and I'll probably switch between those two terms today. The other important thing to realize is that these microbes are not just in our gut, but they're all over our body. They're in our nose, they're in our mouths, they're on our skin. And so basically anywhere that the environment can get to in our body, which includes inside our digestive tract, of course, is colonized with microbes. And the vast majority of these are in our distal gut and in our colon, and so this is the gut microbiota or gut microbiome.”