THE NOTION OF A PERSON OF TRUST: Introduced by the law dated March 4th 2002, the person of trust is there to accompany the patient in all his/her measures of care; this person is also conceived as an helper in medical decisions or when the patient participates in biomedical research protocols. DESIGNATION MODALITIES: Any adult, unprotected patient can designate a person of trust, whose intervention is not only limited to hospitalisation (the nursing staff are obliged to propose such a person), but can also intervene during care at home or at the doctor's. The designation is made in writing and can be revoked at any time. The person of trust can be a relative, a friend or even the treating physician. A SPECIFIC ROLE: The person of trust can be of help in medical measures in routine medicine when the patients needs to be accompanied, and in the case of diagnosis or serious prognosis, and when the patient is incapable of expressing him/herself.