Objectives: The aim of this study was to determine the toxicity of calcium oxalate on epithelial cells of proximal kidney types LLC-PK type I, evaluate the effect of different caffeine concentrations in stopping the crystallization of calcium oxalate in the cellular model of oxalate urolithiasis of proximal kidney tubules – LLC-PK type I. Furthermore, the aim was to determine the level of cell loading by free radicals by measuring the glutathione concentration (GSH) after the treatment with calcium oxalate and caffeine and to determine cell viability with increased caffeine concentrations. Study design: Laboratory research study Materials and methods: The used cell culture is the Lilly Laboratories Cell Porcine Kidney, a cell line produced from the kidney of a normal, healthy male pig (Sus scrofa) between 3 and 4 weeks of age. The chemicals used included caffeine (Sigma) and calcium oxalate (Sigma-Aldrich). The cells were cultured in six-well plates and treated with calcium oxalate and caffeine at appropriate concentrations. After incubation at 37 °C, 5 % CO2, light microscopy followed the formation of crystallization and the effect of caffeine activity after one, three and 24 hours, and EVOSTM FL Color microscope was used to make microphotographs. Total Glutathione Concentration (GSH) was measured spectrophotometrically by using a commercially available kit (Glutathione Assay Kit, Sigma-Aldrich, Saint Louis, MO, USA). The cell susceptibility in suspension was determined by an exclusive Trypan Blue dye (Sigma-Aldrich, St. Louis, USA) using Neubauer's hemocytometer by means of medium-light microscopy. Results: By the proportional increase in concentration, caffeine stops the crystallization of calcium oxalate in the cellular model of oxalate urolithiasis of proximal kidney tubules – LLC-PK type I. Caffeine as a potential protective therapy causes significant cell survival. Overall glutathione expression showed that oxidative damage to cells treated only with calcium oxalate was higher compared to cells treated by both calcium oxalate and caffeine. Conclusion: Caffeine prevents crystallization of calcium oxalate monohydrate in the cellular model of oxalate urolithiasis of proximal kidney tubules LLC-PK type I.