The human microbiome is a complex and complimentary ecological system that is seeded in baby’s at birth. Emerging evidence is demonstrating a role in human physiological that has caused microbiome to be considered a complete human system by some people. The module aims to introduce to you to the concept of the human microbiome, to its evolution in the human being, role in health and well-being, as well as some of the insults which impact on a functioning system.