Ask a Scientist: Microbial Ecologist Jack Gilbert

Microbial Ecologist Jack Gilbert explains that the human microbiome is the bacteria, the fungi, and the viruses that we find inside our body. There’s around a hundred trillion cells of bacteria and viruses inside our body, and they outnumber our own human cells by about two to three times. They weigh around two to three pounds, which is about the same weight as your brain.