The National Cancer Institute (NCI) recently acquired a large supply of formulated products of amygdalin manufactured by Cyto Pharma of Mexico, for possible use in a clinical trial in the US. Tablets for oral administration and ampules of the injectable produce were obtained. Both forms were extensively analyzed and evaluated by several analytic and pharmaceutical laboratories under contract with the NCI. Analytic test procedures were developed to determine the chemical integrity and quantitative composition of the formulated products. Routine physical and biologic tests were also performed to evaluate the manufacturing quality of both dosage forms. The results indicate that both the oral and injectable forms of amygdalin were substandard by US criteria for manufactured pharmaceutical products. All samples were determined to be chemically subpotent, mislabeled, and of poor manufacturing quality. More than 20 samples of the ampules were found by visual inspection to contain microbial contamination. Other samples were found to be pyrogenic. Based on the results of the testing performed, both tablet and ampule forms of amygdalin manufactured by Cyto Pharma of Mexico are considered unfit for use in man.