The biochemistry of phytic acid may be divided into 6 categories: 1) chelation of polyvalent cations to form soluble or insoluble complexes depending on pH, metal-to-phytate ratio, and other factors; 2) formation of an iron chelate that is catalytically inert even in the presence of oxygen, oxy-radicals, and reducing agents; 3) electrostatic interaction with proteins; 4) selective binding to the 2, 3-DPG site of hemoglobin; 5) high affinity adsorption to hydroxyapatite; and 6) interactions with miscellaneous targets. All industrial uses of phytic acid derive from these biochemical reactions. Examples of applications pertaining to each group are discussed.