Laetrile is a compound extracted from the seeds of apricots, peaches, and almonds. It is also known as amygdalin and vitamin B17. This controversial substance is believed by some to have anti-cancer properties, although there is little scientific evidence to support this claim. Other synonyms for laetrile include mandelonitrile beta-glucoside, semidurosin, and nitriloside. Some alternative medicine practitioners also refer to it as "leatrile," "laetril," or "amygdaloside." Despite its popularity among some cancer patients seeking alternative treatments, laetrile is not approved by the FDA and can be dangerous if taken in large doses. It is important to discuss any alternative treatments with a healthcare professional before trying them.