Between science and mystery, the placebo effect is one of the strangest phenomena of medicine. Thanks to him, a few milliliters of water are transformed into an effective pain reliever and a few capsules of sugar can suppress the urge to take a sleeping pill. It's a miracle that lies at the frontier of science, between psychology and physiology, and that paradoxically reveals a great importance in the development of new drugs. Gradually, we are now discovering mechanisms. And for the first time, American researchers have managed to see the placebo effect that occurs in our brain, using imaging techniques. And what about homeopathy ? Is it more effective than the elixir rabbit hair of the Far West ? Anyway, the famous placebo effect may be even more powerful than we imagine !