Practice of Medicine is essentially centered on the doctor-patient relationship. All recommendations are supported by levels of evidence but must be centered on the patient’s needs and rights. Patients have to clearly understand the physician’s recommendation, and the doctor should guide them in a qualified decision-making process. Many medical interventions are dictated by decision algorithms and classified by the level of recommendation, whose understanding must be shared with the patient. A therapeutic index defines the risks and benefits and guides the cost-effectiveness of each recommendation. Informed consent only exists when the physician is confident that the patient has fully understood the content and scope of the recommendation.