Why Study the Microbiome? The Microbiome has a growing importance in general health, and even more significantly, there is a growing understanding regarding the impact that an individual’s microbiome has on contributing to the cause of disease, influencing disease severity, and affecting a person’s response to medication and treatment. For example, it is now known that an individual’s microbiome affects their ability to manage their weight, is implicated in the development of arthritis, and has a role in various neuropsychiatric illnesses such as autism, schizophrenia, OCD, ADHD, and chronic fatigue syndrome. Furthermore, by comparing patients with the same disease, it has been shown that an individual’s microbiome affects the disease severity of autoimmune disorders, asthma, and infections. Perhaps even more interesting and more relevant is that an individual’s microbiome affects their response to medication including vaccination, through effects on metabolism, efficacy, and toxicity.