[en] The effect of polymer sorbents of styrene or methacrylic type containing thiol groups upon ²⁰³Hg²⁺ absorption from the gastrointestinal tract in rats was studied. Furthermore, after intravenous administration of methyl- or phenylmercury chlorides, the effect of these sorbents upon mercury excretion via feces was studied. The ²⁰³Hg²⁺ absorption significantly decreased when the sorbent [150 mg/rat/48hrs] was administered within 30 minutes after ²⁰³HgCl₂ had been administered into the stomach by probe. The fecal excretion of mercury increased after intravenous administration of Me²⁰³HgCl and application of the sorbent, but there was no significant difference in the excretion with Ph²⁰³HgCl. A significant decrease of the ²⁰³Hg content in the urine, kidneys and in the wall of the gastrointestinal tract corresponded to decreased ²⁰³Hg²⁺ absorption. Increased excretion of ²⁰³Hg administered as Me²⁰³HgCl, was manifested by a significant decrease in the mercury content of the brain. (author)