Our bodies play host to trillions of bacteria and other microbes. 

They live on our skin, in our guts, up our noses. Microbes are found in almost every part of the body. Microbes help us produce vitamins and stimulate our immune system. They break down food and perform many other functions that we need to survive. 

Microbes may sound like uninvited guests, but most live harmoniously in and on our bodies. We need a diverse set of microbes working together to stay healthy. They're an essential part of our systems. 

It turns out they're right where they belong.