Laetrile / amygdalin / apricot kernels

That amygdalin, extracted from apricot kernels and marketed as "vitamin B17", is selectively lethal to cancer cells while sparing healthy tissue, and that its suppression proves the cancer industry protects its revenue.

Developed by Ernst Krebs Sr and Jr from the 1950s. Renaming it "vitamin B17" was a deliberate marketing move to imply a deficiency disease. The Committee for Freedom of Choice in Cancer Therapy made it a political cause in the 1970s; twenty-seven US states legalised it. Steve McQueen's 1980 death at a Mexican laetrile clinic was a turning point in public perception. It remains the template every later suppressed-cure narrative follows.

Laetrile is the most thoroughly tested substance on this page, which is the part the suppression narrative cannot accommodate. The NCI ran a large clinical trial in the early 1980s after sustained public pressure. It was tested, in humans, at the government's expense. It did not work: no cures, no stabilisation, no symptom improvement, and several patients showed cyanide toxicity. A 2015 Cochrane review found no reliable evidence of benefit. The kernel of truth is that amygdalin does release cyanide near tissue; the error is that it does so indiscriminately.