This paper aims to explain the construction of the autonomous subject from Foucault's ethical perspective for the qualitative analysis of interprofessional relationships, patient-professional relationships, and moral ethics critique. Foucault tried to break loose from the self, which is merely the result of a biopolitical subjectivation and constituted an interpersonal level. From this, different elements involved in the decision-making capacity of patients in a clinical setting were analysed. Firstly, the context in which decision-making occurs has been explained, distinguishing between traditional practices involved in self-care and the more modern conceptions that make certain possible transformations. Secondly, an attempt is made to explain the formation of the medicalisation of society using the transformations of what Foucault called "techniques of the self". Finally, the ethical framework for a subject's "self-creation", insisting more on the exercises of self-subjectivation, reinforcing the ethics of the self by itself, the "care of the self", has been explained. The role of the patient is understood as an autonomous subject to the extent that the clinical institution and the professionals involved comprehend how the patient’s autonomy in the clinical environment is constituted. All these elements could generate grounded theory on the qualitative methodology of this phenomenon. The current ethical model based on universal principles is not useful to provide a capacity for patients decision-making, relegating to the background their opinions and beliefs. Consequently, a new ethical perspective emerges that aims to return the patient to the fundamental axis of attention.