In recent years, the study of the microbiota has focused the attention of research through the correct interpretation of the set of microorganisms present in various organic surfaces of different animal species and humans, and on the “Metagenome”, which is the study of the DNA sequences of the microbiota. The researchers' attention was focused in particular on demonstrating the close relationship between the variation of the microbiota and the effects it produces on the state of health or on the causes of various pathologies. This scientific document is a review of the most recent literature on the topic "microbiome and state of health" with the aim of restoring the cardinal role of the genetic, environmental, and dietary variables that alter both our intestinal homeostasis and our health.