A colourless, toxic gas boiling at 26 °C — synonym hydrogen cyanide, chemical formula HCN. Cyanogenic glycosides in various foods — cassava above all, but also edible fungi, flaxseed, and certain stone-fruit kernels — release it on hydrolysis. Proper processing — soaking, fermenting, and thorough cooking — is essential to drive it off and make cyanogenic staples safe to eat. Because it is volatile, traditional preparation methods that include grating, soaking, and open cooking effectively reduce its levels, and food-safety guidance for cassava centres on these steps.