Amygdalin is primarily used in alternative medicine as a purported treatment for cancer, although its efficacy and safety are highly controversial and not supported by robust scientific evidence. It is often marketed as "Vitamin B17" and is found in the seeds of fruits like apricots, peaches, and almonds. Proponents claim it can target and destroy cancer cells, but clinical studies have shown no significant anti-cancer benefits and have raised concerns about its potential toxicity. When metabolized, amygdalin breaks down into hydrogen cyanide, which can be harmful or even fatal in high doses. Due to these risks, its use is discouraged by mainstream medical professionals, and it is banned in some countries.