The case against laetrile: the fraudulent cancer remedy

Cancer. 1980 Feb 15;45(4):799-807. doi: 10.1002/1097-0142(19800215)45:4<799::aid-cncr2820450432>;2-6.


The evidence for the claims that laetrile (amygdalin) can prevent or control cancers has been reviewed. The beta-glucosidase content of cancer tissues is low compared to that of normal liver and small intestine. Cancer tissues contain the enzyme rhodanese in amounts comparable to that of liver and kidney and hence, cannot be attacked selectively by cyanide release through beta-glucosidase action on amygdalin. Amygdalin does not have the properties of a vitamin. Rats have been reared for several generations on diets devoid of cyanogenic glycosides, without developing neoplasms. Experiments with tumor-bearing rodents have demonstrated no curative properties by amygdalin administration. Amygdalin is not as non-toxic as claimed, particularly when ingested orally, and especially when taken with plant material high in beta-glucosidase. The claims for cure and control of cancers in humans have been refuted by distinguished physicians who specialize in the treatment of cancer patients. The writings of laetrile proponents are filled with erroneous and absurd statements. The propaganda for the doctrine of "freedom of choice in cancer treatment" deludes many individuals with treatable cancer to reject proven methods of treatment.

Publication types

  • Review

MeSH terms

  • Amygdalin / therapeutic use*
  • Amygdalin / toxicity
  • Analgesics
  • Animals
  • Cyanides / therapeutic use
  • Euphoria / drug effects
  • Gonadotropins / biosynthesis
  • Humans
  • Legislation, Drug
  • Mice
  • Models, Biological
  • Neoplasms / drug therapy*
  • Neoplasms, Experimental / drug therapy
  • Nostrums*
  • Trophoblasts / metabolism
  • United States
  • Vitamins / therapeutic use


  • Analgesics
  • Cyanides
  • Gonadotropins
  • Nostrums
  • Vitamins
  • Amygdalin