Personalized medicine through the development of modern molecular biology methods makes it possible to apply an appropriate drug to the appropriate patient at the right time. The vision of personalized medicine began in the 1990s, when molecular research and knowledge in proteomics, genomics and genetic testing intensified. Since then, pharmaceutical companies, scientists and regulators have faced the challenges that this vision entailed. Currently, “the era of personalized medicine is already upon us.” In this article I will discuss this new way of treating diseases, including several issues that are implemented in this section of medicine, namely: • Individual variation and their implication in personalized medicine• What is what pharmacogenetics/pharmacogenomics• The goals and benefits of a personal medicine approach• Proteomics and genomics – Bio-analytical techniques used in pharmacogenomics research. The traditional paradigm based on the physiology of the disease which is the search for a drug on the basis of visible symptoms is gradually being replaced by a new approach. The objective of this new approach is to study the molecular mechanisms of the disease and to identify the genes responsible for its creation. This molecular analysis of the disease makes it possible to develop a precise drug acting on a specific target. Additionally, pharmacogenetic testing performed prior to drug therapy will predict how a patient will respond to treatment. Such an approach called predictive, preventive, personalized and participatory P4 is revolutionizing the way medicine is practiced and affecting the process of developing new drugs (S. Jakka and M. Rossbach, 2013). Thus, in modern medical practice, the diagnosis of the disease is a support...... middle of article ......nose of this disease, but the administration of Herceptin has been found to inhibit effectively the activity of the receptor and thus lead to an improvement in the state of health. . Currently, trastuzumab is normally used in this type of breast cancer, but this receptor overexpression must first be identified to ensure the treatment is effective because there are different receptors associated with different types of breast cancer such as BRCA1, BRCA2 or ER positive for which another treatment should be used. be applied. As several breast cancer medications are approved on the market, the doctor may perform pharmacogenetic testing to determine which medication would be best for the patient. The same way of choosing a suitable medication will be carried out for other types of diseases. It is important that each genetic test is validated before it can be used, approved and certified by regulatory bodies like the FDA..