This information describes the common uses of Amygdalin, how it works, and its possible side effects.

Common Name

Apricot pits, vitamin B17, mandelonitrile-beta-glucuronide (semi-synthetic), mandelonitrile beta-D-gentiobioside (natural product), laevorotatory and mandelonitrile, prunasin

How It Works

Amygdalin (Laetrile) has not been shown to treat or prevent cancer. It is associated with serious adverse effects.

Amygdalin (also called Laetrile®) is an extract derived from apricot pits and other plants. It can be broken down by enzymes in the intestine to produce cyanide, a known poison. It was first used in Europe and later in the United States as an alternative cancer therapy. Promoters claimed that the cyanide released from amygdalin selectively killed cancer cells, leaving normal tissue cells unharmed. When fed to laboratory animals that had cancer cells implanted in them, amygdalin did not reduce the tumor size or slow their growth. In a clinical study, cancer patients using amygdalin did not have any benefits but some showed cyanide toxicity.

There is renewed interest in studying amygdalin after the discovery of new anticancer mechanisms. However, cancer patients should not use this product in the current form until more is known about its safety and effectiveness.

Purported Uses

  • To prevent and treat cancer
    Although laboratory experiments suggest anticancer properties, clinical evidence does not support this use. Amygdalin (Laetrile®) has been linked to several cases of cyanide poisoning in cancer patients.

Patient Warnings

  • Cases of cyanide toxicity associated with the use of amygdalin have been reported.
  • There have been reports of contaminated and adulterated products of both injectable and oral forms.

Side Effects

  • Inflammation and redness of the skin.
  • Cyanide toxicity from high doses or prolonged use causing: nausea, vomiting, headaches, dizziness, mental confusion, bluish discoloration of the skin, low blood pressure, drooping eyelids, nerve dysfunction, coma, and death.

Special Point

  • The Food and Drug Administration has banned the sale and use of amygdalin (Laetrile®) due to the risk of cyanide poisoning. For this reason, Laetrile® is only offered at alternative medicine clinics outside the United States. Some clinics use it as a component of multi-modality metabolic therapies. Such therapies generally have not been found effective and are discussed at greater length in a separate monograph about metabolic therapies.