Amygdalin

Amygdalin (from Greek: ἀμυγδαλή amygdálē "almond"), C₂₀H₂₇NO₁₁, is a glycoside initially isolated from the seeds of the tree Prunus dulcis, also known as bitter almonds, by Pierre-Jean Robiquet and Antoine Boutron-Charlard, in 1830 and subsequently investigated by Liebig and Wöhler in 1830. Several other related species in the genus of Prunus, including apricot (Prunus armeniaca) and black cherry (Prunus serotina), also contain amygdalin.

Since the early 1950s, a modified form of amygdalin has been promoted under the names laetrile and "Vitamin B₁₇" as a cancer cure. In reality, neither amygdalin nor any derivative such as laetrile is in any sense a vitamin. Studies have found such compounds to be dangerously toxic as well as being clinically ineffective in the treatment of cancer. Taken by mouth they are potentially lethal because certain enzymes (in particular, glucosidases that occur in the gut and in various kinds of seeds, edible or inedible) act on them to produce cyanide. The promotion of laetrile to treat cancer has been described in the medical literature as a canonical example of quackery, and as "the slickest, most sophisticated, and certainly the most remunerative cancer quack promotion in medical history."