# Laetrile, the apricot-pit compound sold as 'vitamin B17', cures cancer and was suppressed by the FDA and drug industry

**Verdict: Contradicted.** Laetrile does not cure cancer. The one thing supporters could point to for decades, a real clinical test, went against them: the National Cancer Institute sponsored a study led from the Mayo Clinic, published in the New England Journal of Medicine in 1982, that found no cure, no improvement, and no longer survival in patients given laetrile, and it documented several patients with blood-cyanide levels near the toxic range. Amygdalin, the compound behind the label, releases cyanide as the body breaks it down, so the treatment carries a genuine poisoning risk. It is not a vitamin: the 'vitamin B17' name was a marketing invention. No controlled trial before or since has shown benefit, and the FDA has never approved it. The grievances that make the story appealing (distrust of the drug industry, the cost of real treatment, the pull of a cheap natural remedy) are understandable, but the claim itself is false. Rated debunked. This is a record of the evidence, not medical advice.

Category: Science, Space & Technology · Era: 1950s–2020s · First circulated: Amygdalin was tried against cancer in 19th-century Germany and discarded; the modern claim dates to Ernst T. Krebs Sr. and Jr. in the early 1950s, with the 'vitamin B17' framing and the mass Laetrile movement following in the 1970s · Believed by: Patients and caregivers drawn to alternative and natural-health treatment, sustained since the 1970s by 'health freedom' and anti-FDA campaigners and, today, by online sellers of apricot kernels and amygdalin
URL: https://theconspiratory.com/theory/laetrile

## Summary
Laetrile is one of the most famous 'suppressed cancer cure' stories in American history. A compound derived from apricot and other fruit pits, marketed under the invented name 'vitamin B17', it was promoted from the 1950s as a natural cancer treatment that the medical establishment and the FDA were said to be hiding to protect profits. In the 1970s it became a genuine mass movement: tens of thousands of patients sought it out, more than twenty states passed laws to legalize it, and the fight reached the Supreme Court. Then it was actually tested. A National Cancer Institute study run from the Mayo Clinic and published in the New England Journal of Medicine in 1982 found no benefit and warned of cyanide poisoning. This case file lays out that record. It separates the real grievances behind the belief from the claim itself, and finds the claim debunked. It offers no medical advice and recommends no treatment; it reports what the evidence and the health authorities establish.

## The claim
That laetrile (also sold as amygdalin or 'vitamin B17'), a substance from apricot kernels and other fruit pits, is an effective and natural cure for cancer; that it is a vitamin whose absence causes cancer; and that the FDA, the drug industry, and organized medicine have suppressed it to protect the profits of conventional cancer treatment.

## Origin and timeline
- 1830s: French chemists Pierre-Jean Robiquet and Antoine Boutron-Charlard isolate amygdalin from bitter almonds. It is a naturally occurring cyanogenic compound, meaning it releases cyanide when broken down, and this chemistry is understood long before any anticancer claim is attached to it.
- 1892: Amygdalin is tried as a cancer treatment in Germany and abandoned as both ineffective and too toxic. The idea lies dormant for decades before being revived in mid-century America.
- 1950s: Ernst T. Krebs Sr. and his son Ernst T. Krebs Jr. begin promoting a preparation of amygdalin, which they trademark as 'Laetrile', as a cancer treatment. The California Cancer Advisory Council later reviews scores of case histories submitted by proponents and finds no evidence of effectiveness.
- 1970s: Krebs Jr. advances the theory that cancer is a deficiency disease and rebrands the compound 'vitamin B17'. It is not a vitamin and no nutrition authority recognizes it as one, but the label reframes a failed drug as a missing nutrient and helps turn laetrile into a national movement.
- 1976–1981: Backed by 'health freedom' campaigners and groups such as the Committee for Freedom of Choice in Cancer Therapy, more than twenty US states pass laws legalizing laetrile within their borders, even as the FDA continues to bar its interstate sale as an unapproved new drug.
- 1979: In United States v. Rutherford, 442 U.S. 544, the Supreme Court rules unanimously that the Food, Drug, and Cosmetic Act's safety and effectiveness standards apply even to terminally ill patients, reversing lower courts that had tried to carve out an exception for laetrile. The Court declines to create a right to an unapproved drug.
- 1980: Actor Steve McQueen, dying of pleural mesothelioma, travels to a clinic in Mexico for an unconventional regimen that includes laetrile. He dies in Juarez on November 7, 1980, hours after surgery to remove a tumor. His high-profile case becomes one of the most cited cautionary stories about the treatment.
- 1982: The National Cancer Institute sponsors a clinical study of laetrile led by Charles Moertel of the Mayo Clinic across four centers. Published in the New England Journal of Medicine, it finds no benefit in 178 patients and documents several with blood-cyanide levels approaching the toxic range. It remains the definitive clinical verdict.
- 2000s–2020s: With US sale banned, laetrile and apricot kernels are marketed online and through alternative clinics abroad, notably in Tijuana and elsewhere in Mexico. Regulators periodically act against sellers, and health agencies continue to warn of cyanide poisoning from apricot-kernel and amygdalin products.

## The evidence, claim by claim
- Claim: Laetrile cures cancer; the establishment simply refuses to test it fairly.
  Evidence: It was tested fairly, and it failed. In the NCI-sponsored study led from the Mayo Clinic and published in the New England Journal of Medicine in 1982, laetrile was given to 178 cancer patients along with the 'metabolic therapy' its promoters recommended. Not one patient was cured or stabilized; there was no meaningful improvement and no extension of life, and disease progressed in the great majority within months. A 2015 Cochrane systematic review reached the same conclusion: no reliable evidence that laetrile or amygdalin has any beneficial effect on cancer.
- Claim: Laetrile is 'vitamin B17', a natural nutrient whose deficiency causes cancer.
  Evidence: It is not a vitamin. No nutrition authority recognizes any 'vitamin B17'; the name was coined by Ernst Krebs Jr. as marketing, and there is no such thing as a laetrile deficiency and no evidence cancer is caused by lacking it. Cancer Research UK, the National Cancer Institute, and Memorial Sloan Kettering all state plainly that laetrile is not a vitamin and has not been shown to treat cancer. Calling it a vitamin was a way to reframe an unapproved drug as a wholesome missing nutrient.
- Claim: It is a harmless, gentle natural remedy with nothing to lose by trying.
  Evidence: Amygdalin releases hydrogen cyanide as the body breaks it down, so the risk is real, not hypothetical. The 1982 trial recorded patients with blood-cyanide levels approaching the toxic range, and health authorities have documented cyanide poisoning, including deaths, particularly after laetrile or apricot kernels are taken by mouth. The FDA bars its sale for this reason, and Cancer Research UK and Memorial Sloan Kettering both warn of serious cyanide toxicity. A remedy that can poison you is not a harmless thing to try.
- Claim: The FDA and the courts suppressed laetrile to protect drug-industry profits.
  Evidence: The record shows a treatment that was regulated because it was unproven, not because it worked. The FDA never approved laetrile because no substantial evidence of safety and effectiveness was ever submitted, the standard the law requires of any new drug. In United States v. Rutherford (1979) the Supreme Court held unanimously that those standards apply even to the terminally ill. Meanwhile more than twenty states legalized laetrile in the 1970s, so it was widely available and still did not produce the cures its promoters promised. Wide access, not suppression, was what finally undercut the claim.
- Claim: Steve McQueen's story and thousands of testimonials prove it works.
  Evidence: Testimonials are not evidence of a cure, and the McQueen case cuts the other way. He sought a laetrile-based regimen in Mexico while dying of an aggressive mesothelioma and died within months; his oncologists and the reporting at the time framed it as a warning, not a success. Anecdotes suffer from survivorship bias: people who improve (often while also receiving conventional treatment, or with slow or curable disease) become vivid stories, while those who rely on laetrile alone and die are not there to tell theirs. Controlled trials exist precisely to see past that, and they found no effect.

## Why people believe it
- A cancer diagnosis is terrifying, and conventional treatment can be harsh and uncertain. The promise of a gentle, natural cure offers hope, and the idea that it is being withheld offers somewhere to aim the fear and anger. That is a deeply human response, not a foolish one.
- The distrust has real fuel. Drug companies have genuinely misled the public and priced treatments beyond many patients' reach, so the leap to 'they would bury a cheap cure too' feels small rather than far-fetched, even though it does not follow.
- The 'vitamin' framing is disarming. Recasting an unapproved drug as a missing natural nutrient, 'vitamin B17', makes a fringe chemical sound wholesome and safe, and makes refusing it sound like the strange, suspicious act.
- Laetrile became a political cause, not just a medical one. The 1970s 'health freedom' movement wrapped it in the language of personal liberty and choice, so the state's refusal to approve it read as an attack on rights rather than a judgment about evidence.
- Anecdote and survivorship bias are persuasive. A person who took laetrile and lived, often alongside real treatment or with a slow-growing cancer, becomes living 'proof', while the people it did not save are no longer around to balance the story.

## Open questions
- Why terminally ill patients should be allowed to try unproven drugs was a genuine ethical and legal question, argued all the way to the Supreme Court in United States v. Rutherford. The Court said no, but the underlying debate about access to experimental treatment is real and continues in 'right to try' laws, separate from any claim that laetrile works.
- Amygdalin still draws laboratory research: cell and animal studies are published periodically, and the cyanide it releases is even of theoretical interest for targeted drug design. None of this is hidden, and none of it has produced evidence that laetrile treats cancer in people; open study of a molecule is not the same as a proven therapy.
- The distrust that powered the movement points at real failures in medicine (drug pricing, industry dishonesty, buried trial data) that are worth fighting on their own terms. Those failures are genuine; they are simply not evidence that this particular remedy was suppressed because it worked.
- Apricot kernels and amygdalin are still sold online and through clinics abroad despite the ban, which raises a live regulatory and consumer-safety question about enforcement and cyanide-poisoning risk, distinct from the settled question of whether the treatment is effective.

## Sources
- Laetrile/Amygdalin (PDQ) - Patient Version, National Cancer Institute: https://www.cancer.gov/about-cancer/treatment/cam/patient/laetrile-pdq
- Laetrile/Amygdalin (PDQ) - Health Professional Version, National Cancer Institute: https://www.cancer.gov/about-cancer/treatment/cam/hp/laetrile-pdq
- A Clinical Trial of Amygdalin (Laetrile) in the Treatment of Human Cancer, Moertel CG et al., New England Journal of Medicine (via PubMed) (1982): https://pubmed.ncbi.nlm.nih.gov/7033783/
- Laetrile treatment for cancer (systematic review), Milazzo S, Horneber M, Cochrane Database of Systematic Reviews (2015): https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD005476.pub4/full
- Amygdalin (Laetrile), Memorial Sloan Kettering Cancer Center: https://www.mskcc.org/cancer-care/integrative-medicine/herbs/amygdalin
- Laetrile (amygdalin or vitamin B17), Cancer Research UK: https://www.cancerresearchuk.org/about-cancer/treatment/complementary-alternative-therapies/individual-therapies/laetrile
- United States v. Rutherford, 442 U.S. 544 (1979), Supreme Court of the United States (via Justia) (1979): https://supreme.justia.com/cases/federal/us/442/544/
- The Rise and Fall of Laetrile, Quackwatch: https://quackwatch.org/related/cancer/laetrile/
- The death of Steve McQueen, who turned to controversial cancer therapy, United Press International (UPI Archives) (1980): https://www.upi.com/Archives/1980/11/08/The-death-of-Steve-McQueen-who-turned-to-controversial/4612342507600/

Rated by The Conspiratory, a neutral, sourced encyclopedia of conspiracy theories. Full page: https://theconspiratory.com/theory/laetrile