The causes of periodontal disease have been descried as malocclusion, trauma from occlusion, local irritants and poor oral hygien. The systemic factor has also been considered as a etiologic factor of periodontal disease. On the other aspect systemic condition could be affected by periodontal disease. For the study of relationships between periodontal disease and systemic condition, twenty patients with periodontal disease and twenty persons with no periodontal involvement were evaluated for inorganic elements and organic materials in the blood. The results of the blood analysis of the two groups were as follows. : Phosphorus and alkline-phoshatase in the group with periodontal disease showed slightly increased phenomenon compared to the control group, and on the other hand calcium and calcium-phosphorus ratio decreased phenomenon. But there is no any significant alteration in the content of each element between the two groups.