# Laetrile (amygdalin, 'vitamin B17')

Source: https://onco.cc/technologies/laetrile-amygdalin/  
OnCo record `laetrile-amygdalin` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Laetrile, sold as vitamin B17 or apricot kernel extract, was tested in a large National Cancer Institute study in the 1980s and did nothing against cancer. It releases cyanide in the gut, and people have been poisoned by it.

## Summary

Amygdalin is a cyanogenic glycoside from apricot, peach and bitter almond kernels; laetrile is a semi-synthetic derivative. Proponents claimed it selectively killed cancer cells. A 1982 NCI-sponsored clinical study of 178 patients found no cure, stabilisation or symptom benefit and several patients with cyanide toxicity, and a 2015 Cochrane review found no randomised or controlled trials supporting any benefit. Oral amygdalin is hydrolysed by gut bacteria to hydrogen cyanide; combined with vitamin C or raw kernels the risk rises, and deaths and severe poisonings continue to be reported. It is banned from sale for cancer in the US and the EU but remains available online and in some clinics abroad. It is the archetype of the unproven cancer cure: plausible-sounding story, no evidence, real harm.

## Fields

- Kind: Technology
- Status: negative
- Last checked: 2026-09-10
- Tags: complementary; supportive-care; evidence:harm
- Principle: The claimed selective release of cyanide inside cancer cells by beta-glucosidase does not occur; cyanide is released systemically by gut flora.
- Strengths: The evidence base is unusually clear, which helps counselling
- Limitations: No efficacy in the NCI study or any controlled trial; Cyanide poisoning, including deaths; Sold illegally online

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Amygdalin
- Cochrane: laetrile treatment for cancer (2015): https://doi.org/10.1002/14651858.CD005476.pub4
- NCI PDQ: Laetrile/amygdalin: https://www.cancer.gov/about-cancer/treatment/cam/hp/laetrile-pdq

## Connected records

- fronts: [Supportive Care & Survivorship](https://onco.cc/fronts/supportive-care/)
- technologies: [Alternative medicine used instead of standard treatment](https://onco.cc/technologies/alternative-medicine-instead-of-treatment/), [Evidence-based integrative oncology](https://onco.cc/technologies/integrative-oncology/)
- bottlenecks: [Misinformation and unproven therapies](https://onco.cc/bottlenecks/b-misinformation/)
- key papers: [Laetrile treatment for cancer](https://onco.cc/key-papers/paper-milazzo-cochrane-database-syst-rev/)
- terms: [Unproven diet claims (alkaline, juice, 'anti-cancer' diets)](https://onco.cc/terms/unproven-diet-claims/)

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