The effects of selenite or selenate supplementation on the concentration and distribution of Fe, Cu, Zn, As, Br, and Rb are investigated using the radioisotope-induced X-ray fluorescence, RIXRF. These effects are studied in the animals bearing BW7756 murine hepatoma and healthy animals for both of the oxidation states. Selenite and selenate induce different effects on the distribution of selenium, zinc, copper, bromine, and rubidium. The differences may be attributed to the differences in the inter element interaction after absorption into the bloodstream as well as to the mode of their intestinal absorption. Simultaneous supplementation of copper with selenite or selenate at the described levels has a profound influence on the concentration levels of other elements in the normal as well as in the diseased mice. The administration of selenium (0.67 micrograms/g body wt sodium selenite or sodium selenate, daily) and selenium and copper (0.67 and 1.35 micrograms/g body wt, respectively) has no effect on the incidence rate of hepatoma development.