[The patient's right to information: the art of communicating].

The article starts by analysing the concept of truth, with its numerous accepted meanings, and then goes on to describe the normal justifications for not telling the truth to patients. This serves as a basis to pose the meaning of being faithful to the truth, with two criteria emphasised: telling the patient "everything" he wants to know, and "only" what he wants to know, using the relevant communication techniques and offering him an adequate "guarantee of support" facing the fragility brought on by his disease. Two extremes are avoided: classical paternalism (systematic avoidance of information given his fragile state) and informational ferocity. Subsequently, the conditions are set out that would exceptionally justify not informing a specific patient, and guidelines are offered to facilitate the suitable communicative process (informational coherence, atmosphere of truth, etc.). Finally, the so-called "conspiracy of silence" is dealt with from an ethical and technical perspective, and there is a reflection on how to measure information within the strategies of communication and deliberation.