The study investigates the effect of chitosan on the formation of calcium oxalate (CaOx) crystals, which are responsible for kidney stones. Chitosan, a biopolymer with potential biomedical applications, was found to accumulate in renal tissue and increase calcium excretion in urine. The researchers evaluated the antioxidant capacity of commercial chitosan and its impact on CaOx crystal formation in vitro. They confirmed the identity of the chitosan using nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). The chitosan showed low to no antioxidant activity but exhibited excellent copper-chelating activity. In vitro experiments revealed that chitosan significantly increased the formation of monohydrate CaOx crystals, which are more prevalent in patients with urolithiasis. Chitosan also modified the morphology and size of these crystals, making them more positively charged, which can facilitate their interaction with renal cells. The study concludes that chitosan may contribute to the formation of kidney stones, but further in vivo studies are needed to confirm these findings.The study investigates the effect of chitosan on the formation of calcium oxalate (CaOx) crystals, which are responsible for kidney stones. Chitosan, a biopolymer with potential biomedical applications, was found to accumulate in renal tissue and increase calcium excretion in urine. The researchers evaluated the antioxidant capacity of commercial chitosan and its impact on CaOx crystal formation in vitro. They confirmed the identity of the chitosan using nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). The chitosan showed low to no antioxidant activity but exhibited excellent copper-chelating activity. In vitro experiments revealed that chitosan significantly increased the formation of monohydrate CaOx crystals, which are more prevalent in patients with urolithiasis. Chitosan also modified the morphology and size of these crystals, making them more positively charged, which can facilitate their interaction with renal cells. The study concludes that chitosan may contribute to the formation of kidney stones, but further in vivo studies are needed to confirm these findings.