In such different fields as human health, animal health, phytosanitary care, or the environment, who has not heard about the microbiome, the microbiota, and even metagenomics? And for good reason! Many sectors are concerned, in particular the cosmetics, pharmaceutical, and chemical industries. But what about the claims associated with this concept? Corinne Benoliel, of Institut Scientis, gave us a few explanations.