A substance found in the pits of many fruits such as apricots and papayas, and in other foods. It has been tried in some countries as a treatment for cancer, but it has not been shown to work in clinical studies. Laetrile is not approved for use in the United States.

Originally, the name laetrile was the contraction of laevo-mandelonitrile glucoside, a cyanogenic glycoside found naturally in some plants. Over the years the meaning of laetrile has changed. There are now preparations called Laetrile where amygdalin is the major constituent. Laetrile and amygdalin are often used interchangeably, but are different agents. Cyanide and benzaldehyde are metabolites of both laetrile and amygdalin. Both metabolites may possess antineoplastic properties. Laetrile has been used as an anticancer treatment in humans worldwide, but scientific evidence does not support its effectiveness. It is not approved for use in the United States. (NCI04)