Background: Curcumin is found in the rhizomes of the turmeric plant that has been showed antioxidant and anti-inflammatory effect. The aim of this study was to evaluate the effects of systemic curcumin therapy on alveolar bone loss in an experimental periodontitis model in rats. Material and Methods: Thirty-two male Wistar rats were randomly divided to 4 groups: 75 mg/kg/daily curcumin (C75; n = 8), 150 mg/kg/daily curcumin (C150; n = 8), Control (n = 8), and Ligated (n = 8). Curcumin was administrated using gastric gavage. After 12 days, the rats were sacrificed. Right mandibles samples were histopathologically examined. Alveolar bone loss was measured. Interleukin 1 beta (IL-1 beta) and interleukin 10 (IL-10) were evaluated in the serum samples and gingival homogenates. Results: The measurements of alveolar bone loss in the mandibular molars revealed significantly higher bone-loss values in the Ligated group than the Control, C75 and C150 groups. The IL-1 beta levels in the gingival homogenates were significantly increased in the Ligated group compared to those of the Control, C75 and C150 groups. The serum IL-1 beta levels in the Ligated group were significantly higher than the Control group. The mean osteoblast numbers in the Ligated group were lower than those of the Control, C75 and C150 groups. The C150 groups showed significantly more osteoblasts than the Control group. The osteoclast numbers in the Ligated group increased significantly compared to the C75, C150 and control groups. Conclusion: This study demonstrates that systemic administration of curcumin at the 75 and 150mg/kg doses reduced alveolar bone loss in the periodontal disease in rats.