Initial pharmacologic studies of amygdalin (laetrile) in man.

A simple enzymatic assay has been applied to the determination of amygdalin in urine and plasma of patients taking laetrile on their own initiative. Following parenteral administration of laetrile, amygdalin is excreted primarily as the unchanged molecule and urinary recoveries may approach 100 percent. Peak plasma levels after a 6 gm intramuscular dose were 180 microgram/ml. The ratio of amygdalin epimers was unchanged in the urine following parenteral injection.