Flipping through Facebook today I saw someone had shared a post titled 'Vitamin B17: the greatest cover-up in the history of cancer.' There's certainly a cover-up here, but not in the way that was intended by the author. Substances labelled 'Vitamin B17', 'laetrile' or 'amygdalin' (technically a slightly different compound) are sold as cancer cures that the pharmacological industry doesn't want you to know about. But they aren't anything of the sort.
Amygdalin is found in apricot pits, while laetrile is a synthetic compound which is similar in structure. Despite the 'vitamin B17' label it is frequently given, this is not a vitamin in any way, shape or form. Amygdalin, which enzymes can break down to give off the deadly hydrogen cyanide, was tested as a cancer treatment over 100 years ago and found both not to work and to be extremely toxic. Neither of these problems seem to have got in the way of those promoting it as a cure.
One of the reasons that laetrile continues to be rediscovered as a supposed cure is that it was heavily marketed by a self-styled doctor, Ernst Krebs who claimed that cancer was caused by a deficiency of 'vitamin B17.' For decades there have been attempts to make money from those suffering from cancer by promoting this unsubstantiated substance as a cure.
A thorough review of studies of the use of laetrile in the treatment of cancer made in 2011 concluded: The claims that laetrile or amygdalin have beneficial effects for cancer patients are not currently supported by sound clinical data. There is a considerable risk of serious adverse effects from cyanide poisoning after laetrile or amygdalin, especially after oral ingestion. The risk-benefit balance of laetrile or amygdalin as a treatment for cancer is therefore unambiguously negative.