This paper rewiew about cyanides pretends to show its roll in our society from the beginning to present time. It inquires on its chemical appearence and stand out its importance in mankind History. Also, it is described both chemicals and forensic techniques to figure out up to date ?in vivo? and ?in vitro? key aspects, its importance in forensics like as a poison, not only punitive fact, but accidental one, proving that prominence at social and industrial, even household, environments of today. Finally, we´ll describe the cyanide´s toxic procedures in the organism and the biochemicals protection which it posseses, in the presence of its toxic effects.