While many drugs have a good therapeutic effect for the majority of patients, in some cases they may show a reduced effect or even cause very serious side effects. As more and more positions of the human genome are identified that are responsible for the above effects in terms of the patient’s response to a drug, pharmacogenomics allows the regulation of medication based on the genetic profile of each patient (where the necessary scientific data are available), thus maximizing the response to the drug with the least possible side effects.