Abstract : More patients are actually treated due to the incredible improvements of medical care, especially in the field of pharmacotherapy. Medical guidelines are based on the results of controlled trials. This kind of medicine, also called Evidence Based Medicine (EBM), is actually the cornerstone of good clinical practice. Nevertheless, it remains a lot of patients disappointed by the fact that they have no medical gain of their treatment. The reason is that each patient has his/her own metabolic characteristics. Better is the characterization of such patients, better will be the treatment targeting them. It is what is called the personalized medicine. To reach this challenge, pharmacogenetic advances would be helpful. From an antagonism between EBM and personalized medicine, this new medical paradigm has to consider these approaches as partners. To reach this goal, medical doctors, legal authorities and pharmaceutical companies have to be responsible in front of these new ethical challenges.