Cyanide has gained historical notoriety as a poison used with intent to cause fatality. Its occurrence in industry is confined to a small number of uses in a relatively narrow range of industries, including the manufacture of Perspex and nylon and in electroplating. With proper controls in these settings, episodes of poisoning are extremely rare. However, because of the potential for a fatal outcome, procedures for the treatment of acute poisoning are essential. Antidotes include methaemoglobin generators, direct binding agents and sulphur donors, but there is a lack of international consensus about the treatment of choice. This article reviews the mechanisms and treatment of cyanide intoxication and emphasizes the importance of having agreed local procedures for the emergency treatment of poisoning.