Electroconvulsive therapy (formerly called sismotherapy, electronarcosis or shock therapy) is a therapeutic tool used in several psychiatric illnesses. It consists in the induction of a generalized convulsive seizure by a transcranial electric stimulation. If it is true that this tool continues to stigmatise the collective imagination in giving rise to dread and suspicion (considered by some people as a barbarian or obsolete therapy), it is however an effective (sometimes irreplaceable) and well tolerated treatment. Over the last decades, ECT has generated renewed interest in psychiatric therapy. It constitutes today the oldest biological therapeutic tool still in use in psychiatry.