Man can be exposed to hydrogen cyanide in many professions as well as otherwise. In World War II the Nazis ušed it in gas chambers under the trade name Cyklon B, in concentration camps mainly for mass extermination of the Jewish population. It is one of the strongest poisons. In the organism it binds to Fe3 in mitochondrial cytochrome oxidase and blocks cellular respiration. The inhibition of cytochrome oxidase stops oxidative phosphorylation and aerobic glucose utilization with all its consequences. Intoxication takés a very rapid and often lethal course. With a certain delay, it develops upon ingestion of cyanide salts, cer- tain organic compounds or plant parts containing cyanogenic glycosides. Presented is the clinical and labo- ratory picture of intoxication as well as detailed information on classical and contemporary treatment with antidotes, which should begin immediately.

        Key words: holocaust - Cyklon B - hydrogen cyanide gas - cyanide salts - intoxication