Flaccid paralysis is very easy to produce in hypnosis and is often used in didactic setting. This paper is aimed at demonstrating that hypnotic flaccid paralysis is a real, measurable and reproducible phenomenon that belongs to the Galilean science and can be studied with the methods of human physiology. Ten participants (5 highly hypnotizable subjects and 5 control patients highly responsive to botulinum toxin) were recruited. Through a non-invasive electromyograph, muscular tension was previously measured (in µV) in all participants at the corrugator muscles of the forehead. The 5 highs then underwent in experimental setting hypnotic induction followed by the suggestion of flaccid paralysis of the corrugators. The 5 control patients received injection of a paralytic dose of botulinum toxin at the level of the corrugators. Both groups were visually observed, and electromyography was repeated while the participant received the commands «corrugate» or «don’t corrugate». Both participants undergoing hypnosis and patients receiving the toxin were patently unable to corrugate. Furthermore, the muscular tension recorded at the corrugator was even lower in the former than in the latter, probably due to the additional relaxing effect of hypnosis. The results demonstrate that hypnotic flaccid muscular paralysis is real, and open a way to use hypnotic commands in preventing unconscious corrugation that leads to irreversible dermal fractures of foreheads. In this indication, hypnosis could be more effective (and of course less invasive) that injection of botulinum toxin. Long-lasting studies are mandatory to confirm the present results recorded in acute experimental setting.