[Placebo: real or imagined effect. What does the science say?].

The placebo effect is one of the mechanisms at work in the success of comprehensive care. It relies on psychological, biological and environmental mechanisms. If its effectiveness has been documented, it should be noted that its power of effect remains weak and that it depends on the context. Although real, the placebo effect is remembered to be associated with manipulation concerning the success of a treatment, we pose as an ethical defender of its use. This article aims to recall the psychobiological mechanisms at work and to replace the placebo effect in clinical practice.