Wikipedia Article About Oil of bitter almonds on Wikipedia The bitter almond is rather broader and shorter than the sweet almond, and contains about 50% of the fixed oil which also occurs in sweet almonds. It also contains a ferment emulsion which, in the presence of water, acts on a soluble glucoside, amygdalin, yielding glucose, cyanide and the essential oil of bitter almonds or benzaldehyde. Bitter almonds may yield from 6 to 8% of prussic acid (also known as hydrogen cyanide). Extract of bitter almond was once used medicinally but even in small doses effects are severe and in larger doses can be deadly; the prussic acid must be removed before consumption.