Pharmacogenetics has a long history.

It is now known that differences in responses to therapy are largely due to heredity. In particular, up to 50% of all adverse reactions are determined by genetics. However, the connection between genes and responses to treatment was not immediately identified.

The origins of pharmacogenetics go back to the time of Pythagoras. At the end of the 19th century, the famous Canadian physician William Osler noted the influence of individual differences in patients on their treatment. At the beginning of the 20th century, the English physician Archibald Garrod observed patients with alkaptonuria, a rare related disease based on a disorder of amino acid metabolism.

During World War II, a number of American soldiers receiving primaquine (an antimalarial drug) experienced high fever, head and abdominal pain, anemia, etc. It was noted that these symptoms were experienced exclusively by soldiers of African descent. This gave grounds to draw conclusions about the genetic nature of the disease.