Laetrile, also known as amygdalin, is a substance promoted as an alternative cancer treatment since the 1970s. It is derived from apricot pits and produces cyanide when metabolized. While some claim it selectively kills cancer cells, evidence shows it is toxic and there are no well-designed studies proving its effectiveness as a treatment. Reports of benefits are unreliable and risks include cyanide poisoning and unknown purity of sources being used. Many health authorities have banned its use due to lack of evidence and risks of toxicity.