INTRODUCTION: Periodontitis is a common chronic inflammatory disease characterized by the destruction of the supporting structures of the teeth. The host defense mechanisms are responsible for inflamatuar and destructive reactions in periodontitis. Celastrol is one of the most promising components of the plant in Eastern and Southern China that has a long history of use in traditional medicine for the treatment of inflammatory conditions. AIM: The aim of this animal study was to inspect the preventive or restrictive effects of celastrol on periodontitis-related inflammatory host response and alveolar bone loss. METHODS: 24 male Sprague Dawley rats were randomly assigned into 3 groups: control, experimental periodontitis (Ep), and experimental periodontitis-celastrol (Ep-Cel). Periodontitis was induced by placing ligatures sub-paramarginally around the mandibular first molars of the rats in the Ep and Ep-Cel groups and maintaining the ligatures for 15 days. For 14 days following the ligature placement, celastrol administration (1 mg/kg BW day) for the Ep-Cel group and vehicle injection for the control and Ep groups was carried out. At the end of the experiment, mandibula and gingiva samples were obtained after the euthanasia. Alveolar bone loss was measured on serial histological slices; Tumor Necrosis Factor-α and Interleukin-1β levels were measured on gingiva samples by ELISA. RESULTS: Systemic celastrol administration significantly restricted the alveolar bone loss that was higher in rats with periodontitis. (p < 0.05) Tumor Necrosis Factor-α and Interleukin-1β levels that were high in the gingiva of the rats with periodontitis were found significantly lower in rats administered celastrol. (p < 0.05). CONCLUSION: Celastrol restricted periodontitis-related alveolar bone loss by suppressing the inflammatory response.