In this interview Nicola Davis, who writes about science, health and the environment for The Guardian and Observer and who was the editor in charge of Observer Tech Monthly exposes the true role of microbiota in people’s health. In fact, he clarifies that the intestinal microbiome in particular has been linked to a large number of diseases and conditions, from diabetes to autism, anxiety and obesity. The microbiome has also been linked to the way people respond to certain medications, including how cancer patients respond to chemotherapy, and it has been suggested that it might be related to the way we sleep.