The interruption of life support poses different problems for he who interrogates himself regarding the possible juridical role of omissible behaviour or activities by part of the physician when dealing with end-of-life interventions within the boundary of life and death. The present contribution proposes to trace the coordinates necessary to answer the main query regarding the obligations which may be incumbent on the physician. For this reason, the necessity to interpret the legal sanctions in a technical key is highlighted. This is performed in sight of a progressive and inevitable adaptation to problems which are the result of a social evolution, and to the conception of values which consitute an object responsibility, as renewed by the constitution. The laws that discipline crimes against life and individual integrity must be interpreted while keeping in mind that the objective of maintaining the patient in life must be integrated with the control of suffering and the guarantee of a dignified death. When identifying the principles which have to inspire the decisions during ‘borderline or boundary situations’, it is highlighted the way the physician has to resort to a just equilibrium between benefit, which can be reasonably expected, and sacrifice, which should be imposed, taking into consideration the criteria of good clinical practice, among which attention to the patient’s will must be taken into consideration.