The aims of the study were to evaluate the impact of a written information about treatment related risks in patient receiving blood derived or recombinant medications. Haemophiliac patients and patients with constitutional or acquired immune deficiencies are concerned by this treatment and these information. Our objectives are to evaluate the efficacy of the written information, the knowledge of the patients about these medications and the psychological, emotional impact if these information. The study is based on questionnaires which specified how the patient treat bleeding episodes, their knowledge about viral safety of blood products, the patient's perception of his or her health status and relationship with the physician. Psychological and emotional status are evaluated with the Hospital Anxiety and Depression Scale. The results show the difficulty to inform patients: if the information generate only limited anxiety in patients with haemophilia or immune deficiencies, we observe that the delivery of a written information got a mediocre effect on overall knowledge. We think that this information must be appropriate for patients and be communicated orally within the patient-physician relationship.