Phytic acid (IP6) is an inositol-derivative that has undergone phosphorylation and belongs to nutraceuticals of the high-fiber diet. This compound has a broad spectrum of biological activities, though the in vitro and in vivo anticancer activity was described. There has been observed an inhibition of tumor growth and induction of cell differentiation in the presence of IP6 in a few cancer cell lines including colon, nipple, breast, prostate, cervix, liver, pancreas, melanoma and glioblastoma. Molecular mechanisms of the IP6 mediated anticancer activity have not been fully specified. According to the current state of knowledge there can be only assumed a few ways of action. Antioxidant properties, participation in signal transduction, ability to enhance NK-cells, inhibiting influence on cell cycle, induction of differentiation in transformed cells and activation of programmed death pathways are taken into consideration.