OBJECTIVES: This study aims to explore the therapeutic effects of medical ozone therapy on the frozen shoulder (FS) model and compares it with traditional corticosteroid treatments in rats. MATERIALS AND METHODS: A total of 30 Sprague-Dawley rats aged 18 to 20 months weighing between 400 to 450 g were included in the study. The rats were randomly divided into three equal groups: a control group (C, n=10, FS model only), a corticosteroid treatment group (CST, n=10, FS model + intraarticular 0.5 mg/kg betamethasone), and an ozone treatment group (OT, n=10, FS model + intraarticular 1 mg/kg ozone). Frozen shoulder was induced via surgical immobilization, and treatments were administered intraarticularly. Outcomes were measured through histopathological and functional assessments. RESULTS: The CST and OT significantly reduced inflammation (p<
0.002), capillary proliferation (p<
0.002), fibroblastic proliferation (p=0.002), collagen type 3 staining (p=0.022), and mean capsular thickness (p<
0.002), while improving the range of motion in all directions compared to the control group. Ozone therapy showed a comparable reduction in fibrosis and improvement in joint mobility to CST (p=0.002). CONCLUSION: Ozone therapy effectively reduces fibrosis and improves mobility in an FS rat model, presenting a promising alternative to corticosteroids. However, further studies are still needed to elucidate the molecular mechanisms and optimize treatment protocols, underscoring the potential for future discoveries in this area.