It is known that the subcutaneous injection of a single dose of sodium selenite into suckling rats results in the development of large nuclear opacities. The intracellular transport of selenite in various cells, except lens cells, occurs via the Cl/HCO3 exchanger. The aim of the present study is to investigate the possible role of the anion-exchange inhibitor, disulfonic stilbene (SITS), in the selenite-induced catarogenesis in the rat pups. Wistar albino rats (8-10 d old) were separated into three groups: one control and two experimental. The first experimental group was injected subcutaneously with a single dose of 30 nmol sodium selenite/g body weight. The second experimental group was injected with a single dose of 10 nmol SITS/g body weight 15 min before the same dose selenite injection. The control group did not have any injections. The stage of cataract development was examined on d 7 postinjection with slit-lamp photographs. In SITS pretreated group, all eyes remained transparent (considered as stage 0), whereas in the selenite-injected group, the animals did have different stage of nuclear cataract; 8 animals have stage 5, 10 animals have stage 4, and 4 animals have stage 3. A pretreatment of SITS completely prevented cataract formation of the selenite-induced cataract model in rat pups.