Unproven methods of cancer management: Laetrile

Abstract

“Laetrile” is used interchangeably with “amygdalin” to designate naturalsubstances, derived primarily from apricots and almonds, that can releasecyanide, which is lethal to living organisms. In the 1920s, Dr. Ernst T. Krebs, Sr., formulated a theory that amygdalin could kill cancer cells. Histheory was inconsistent with biochemical facts and has since been modifiedat least twice by his son, Ernst T. Krebs, Jr. Extensive work has been doneby cancer scientists to test the claim that Laetrile fights cancer. Manyanimal experiments in the 1970s showed a complete lack of tumor killing byLaetrile. Reviews of the medical records of patients whose cancers wereclaimed to be reduced or cured after Laetrile treatment found insufficientmedical evidence to judge Laetrile's efficacy. Finally, in a clinical trialin cancer patients reported in 1982, Laetrile neither caused shrinkage oftumors, nor increased survival time, nor alleviated cancer symptoms, norenhanced well-being. Several reports in the medical literature documentinstances in which Laetrile has caused serious, life-threatening toxicitywhen taken in large doses in the manner prescribed by Laetrile advocates. In light of the lack of efficacy of Laetrile and its demonstrated abilityto cause harm, Laetrile should not be used to treat cancer.