Laetrile Chemical formula

Chemical information

CAS — 1332-94-1 (laetrile); 29883-15-6 (amygdalin).


Laetrile is the term used for a product consisting chiefly of amygdalin, which is the major cyanogenic glycoside of apricot kernels. Amygdalin is Rα-cyanobenzyl-6-O-β-D-glucopyranosylβ-D-glucopyranoside (C20H27NO11= 457.4). Laetrile is also used as a term for Rα-cyanobenzyl-6-O-β-D-glucopyranosiduronic acid (C14H15NO7= 309.3). Laetrile was claimed to be preferentially hydrolysed in cancer cells by β-glucosidases to benzaldehyde and hydrogen cyanide, which killed the cell, but amygdalin does not appear to be absorbed from the gastrointestinal tract, and both normal and malignant cells contain only traces of β-glucosidases. Laetrile has also been claimed to be ‘vitamin B17’, the deficiency of which is said to result in cancer; there is no evidence for this view and laetrile is of no known value in human nutrition. There have been several reports of cyanide poisoning and other adverse reactions associated with the use of laetrile, especially when taken orally. Further references2-4 to laetrile, including case reports3,4 of toxic effects.
1. Milazzo S, et al. Laetrile treatment for cancer. Available in The Cochrane Database of Systematic Reviews; Issu
2. Chichester: John Wiley; 2006 (accessed 17/07/08)
2. Chandler RF, et al. Controversial laetrile. Pharm J 1984; 232: 330–2
3. Bromley J, et al. Life-threatening interaction between complementary medicines: cyanide toxicity following ingestion of amygdalin and vitamin C. Ann Pharmacother 2005; 39: 1566–9
4. O’Brien B, et al. Severe cyanide toxicity from ‘vitamin supplements’. Eur J Emerg Med 2005; 12: 257–8.
Published May 08, 2019.