[Skip to Content]
[Skip to Content Landing]
February 13, 1981

A Pharmacologic and Toxicological Study of Amygdalin

Author Affiliations

From the Departments of Oncology (Drs Moertel, Ames, Kovach, Moyer), Laboratory Medicine (Dr Moyer), and Anesthesiology (Dr Tinker), Mayo Clinic and Mayo Foundation, Rochester, Minn.

JAMA. 1981;245(6):591-594. doi:10.1001/jama.1981.03310310033018

Six patients with advanced cancer were treated with amygdalin (laetrile) at dosages similar to those employed by laetrile practitioners. Amygdalin given intravenously at 4.5 g/sq m/day was largely excreted unchanged in the urine and produced no clinical or laboratory evidence of toxic reaction. Amygdalin given orally at 0.5 g three times daily produced significant blood cyanide levels to 2.1 μg/mL. No clinical or laboratory evidence of toxic reaction was seen in the six patients taking oral amygdalin at this dosage. One patient, however, challenged with a large intake of raw almonds, had transient symptoms of cyanide toxic reaction with escalating blood cyanide levels. This small study indicates that amygdalin in the doses employed produces few clinical side effects. A definite hazard of cyanide toxic reaction must be assumed, however, and possible long-term side effects remain unknown.

(JAMA 1981;245:591-594)