Vitamin B17 affects cancer cells, but the effect is not therapeutic. Normal cells have an enzyme called rhodanese, which inactivates the cyanide molecule of the Vitamin B17 while cancer cells lack this enzyme and thus the vitamin hastens their death. The vitamin can, however, not be used as a cancer cure because it would also intoxicate the healthy normal cells as well.
what is vitamin b17 used for? – http://www.ehow.com/about_5038800_vitamin-used.html