Pharmacogenetics is the study of how people respond differently to drug therapy based upon their genetic makeup or genes. Diet, overall health, and environment also have significant influence on medication response, but none are stronger indicators of how you will process medication than your genetics.Pharmacogenetics is not new - An article was published in 1957 by a geneticist who noted that adverse reactions to an anti-malarial drug and a muscle relaxant were inherited and linked to deficiencies in the activity of specific liver enzymes which were responsible for the breakdown or metabolism of those particular drugs. This article established the link between genetics and the enzymes that break down medications while simultaneously establishing the link between that process and adverse reactions to the medications themselves.