Index to Information on Laetrile


Stephen Barrett, M.D.
September 11, 2020

Laetrile is the trade name for a synthetic relative of amygdalin, a chemical in the kernels of apricot pits, apple seeds, bitter almonds, and some other stone fruits and nuts. Proponents claim that Laetrile kills tumor cells selectively while leaving normal cells alone. Many have called it “vitamin B17” and falsely claimed that cancer is a vitamin deficiency disease that Laetrile can cure. Although Laetrile has been promoted as safe and effective, clinical evidence indicates that it is neither. When subjected to enzymatic breakdown in the body, it forms glucose, benzaldehyde, and hydrogen cyanide. Some patients treated with Laetrile have suffered nausea, vomiting, headache, and dizziness, and a few have died from cyanide poisoning. Tests of Laetrile in at least 20 animal tumor models have found no benefit either alone or together with other substances. Studies of human case reports have also been uniformly negative. 

In 1975 a patient named Glen Rutherford filed a class-action suit to stop the FDA from blocking the distribution of Laetrile. Early in the case, a renegade federal district court judge ruled that cancer patients could import a 6-month supply of Laetrile for personal use if they could obtain a physician’s affidavit that they were “terminal.” In 1979 the U.S. Supreme Court ruled that it is not possible to be certain who is terminal and that even if it were, both terminally ill patients and the general public deserve protection from fraudulent cures. In 1987, after further appeals were denied, the affidavit system was terminated. Today few sources of Laetrile are available within the United States, but it still is utilized at Mexican clinics. In 2011, a Cochrane review concluded that there is no reliable evidence for the alleged effects of Laetrile or amygdalin for curative effects in cancer patients. 

Critical Articles
FDA Laetrile Rulemaking Proceeding
The Rutherford Case
Other Civil Cases
Criminal Prosecution
Licensing Board Actions
Proponent Organization
Proponent Publications