The coexpression of ACE-2 in alveolar type 2 cells and intestinal and colonic epithelial cells, the consequent viral replication not limited to the respiratory system but also involving the gut and the clinical presentation of SARS-CoV-2-infected patients often including diarrhea other than the classical respiratory symptoms, are all elements pointing towards a possible link between the microbiota and the current pandemic infectious disease known as COVID-19. The gene discussed is ACE2; the disease is COVID-19.