The efficiency of an active substance (AL) prepared in our laboratory as a composite sorbent on the basis of hexacyanoferrates (II) bound on pearl cellulose, in affecting the radiocesium (Cs-137) retention in white miniature pigs was investigated. The function of the composite sorbent in dependence on the way of administration, i.e. its effect on a decrease of primary resorption and its ability to interrupt the enteral cycle was studied, too. The efficiency of stable cesium administration in the form of CsCl in the same process was also determined. It was proved that AL accelerated significantly the excretion through its effect both on primary resorption causing an approx. 11-fold reduction of resorption when administered simultaneously with radiocesium and on the enteral cycle, causing an approx. 3.5-fold increase of excretion of Cs-137 when administered daily. Thus the composite sorbent (AL) administered at long-term along with contaminated feed reduced the equilibrium concentration of radiocesium in meat 30-40 times. This might be of great importance in the time of nuclear emergencies. On the other hand, administration of non-active Cs at a level up to 1 mg Cs/1 kg of liveweight had no significant effect on Cs-137 elimination.