Cyanide is a chemical compound containing a cyano group (a carbon atom triple-bonded to a nitrogen atom). Cyanide compounds are highly toxic. They bring about asphixiation and kill almost instantly. When cyanide has been used, there is usually the characteristic smell of bitter almonds.
- Hydrogen cyanide, also called prussic acid. A liquid. The fumes of this could be inhaled.
- Potassium cyanide. A white cystaliine substance which could be added to drinks.
Characters poisoned with cyanide
- Dr Ames - The Adventure of the Egyptian Tomb (suicide). He had tried to poison Poirot with a tisane spiked with cyanide but was exposed. He grabbed the drink and swallowed it himself.
- George Barton - Sparkling Cyanide
- Rosemary Barton - Sparkling Cyanide
- Derek Bradley - Curtain
- Emily Brent - And Then There Were None
- Sir Arthur Carmichael - The Strange Case of Sir Arthur Carmichael
- Adele Fortescue - A Pocket Full of Rye
- Michael Garfield? - Hallowe'en Party (suicide)
- Claudia Hardcastle - Endless Night
- Samuel Long - The Gate of Baghdad (suicide)
- Anthony Marston - And Then There Were None
- Mayerling - The Big Four. He had been gagged and forced to inhale Prussic acid.
- Mary Pritchard - The Blue Geranium
- Ellie Rogers - Endless Night
- Iris Russell - Yellow Iris
- Mona Symmington - The Moving Finger
- Ella Zielinsky - The Mirror Crack'd from Side to Side