Hypnosis is a technique allowing the patient to focus his mental attention on a thought or a sensation, with the aim of reducing or modulating the intensity of a negative feeling or an ordeal encountered during the course of treatment. This tool can be used when patients are faced with chronic disorders (pain, anxiety, ...) or iatrogenic effects (nausea, asthenia, ...). The patient is referred to hypnosis care by the doctor, psychologist or paramedics who follow him, when they detect a need. Several scientific studies have shown the effectiveness of hypnosis in improving the quality of life of patients with breast cancer and in reducing pain during invasive procedures. On the other hand, in hematology, no research has measured the evolution of anxiety, over time, in patients receiving hypnotherapy.