as he later claimed Laetrile was instead a vitamin. Pangamic acid Pangamic acid, also called "pangamate," and "vitamin B15," is the name given to the chemical compound described as d-gluconodimethylamino acetic acid with the empirical formula C10H19O8N and purportedly isolated from apricot seeds. It was initially promoted by Ernst T. Krebs, Sr. and his son Ernst T. Krebs, Jr. as a medicinal compound for use in treatment of a wide range of diseases. They also termed this chemical "Vitamin B15," though it is not a true vitamin, has no nutritional value, has no known use in the long term treatment of any disease and has been called a "quack remedy." Although a number of compounds labelled "pangamic acid" have been studied or sold, no chemical compound, including those claimed by the Krebses to be pangamic acid, has been scientifically verified to have the characteristics that defined the original description of the compound. Amygdalin and laetrile Amygdalin, C20H27NO11, is a glycoside initially isolated from the seeds of a cultivar of the almond tree, Prunus dulcis var. amara, also known as bitter almonds, by Pierre-Jean Robiquet and Antoine-François Boutron-Charlard (1796–1879) in 1830, and subsequently investigated by Liebig and Wöhler in 1830, and others. It was promoted in a modified form called laetrile as a cancer cure by Ernst T. Krebs, Jr. under the name "Vitamin B17", but studies have found it to be ineffective. It is also not a vitamin, and can cause cyanide poisoning. The promotion of laetrile to treat cancer has been described in the scientific literature as a canonical example of quackery, with Irving Lerner of the University of Minnesota describing it as "the slickest, most sophisticated, and certainly the most remunerative cancer quack promotion in medical history." References 1911 births 1996 deaths Alternative cancer treatment advocates American biochemists