Objective:To investigate the differences and similarities of parameters associated with ane-mia of inflammation between patients with stage Ⅲ periodontitis and periodontally healthy volunteers,and to explore the influence of periodontal initial therapy on those indicators.Methods:Patients with stageⅢ periodontitis and periodontally healthy volunteers seeking periodontal treatment or prophylaxis at De-partment of Periodontology,Peking University School and Hospital of Stomatology from February 2020 to February 2023 were enrolled.Their demographic characteristics,periodontal parameters(including pro-bing depth,clinical attachment loss,bleeding index),and fasting blood were gathered before periodontal initial therapy.Three months after periodontal initial therapy,the periodontal parameters of the patients with stage Ⅲ periodontitis were re-evaluated and their fasting blood was collected again.Blood routine examinations(including white blood cells,red blood cells,hemoglobin,packed cell volume,mean cor-puscular volume of erythrocytes,and mean corpuscular hemoglobin concentration)were performed.And ferritin,hepcidin,erythropoietin(EPO)were detected with enzyme-linked immunosorbent assay(ELISA).All data analysis was done with SPSS 21.0,independent sample t test,paired t test,and analysis of co-variance were used for comparison between the groups.Results:A total of 25 patients with stage Ⅲperiodontitis and 25 periodontally healthy volunteers were included in this study.The patients with stageⅢ periodontitis were significantly older than those in periodontally healthy status[(36.72±7.64)years vs.(31.44±7.52)years,P=0.017].The patients with stage Ⅲ periodontitis showed lower serum he-moglobin[(134.92±12.71)g/L vs.(146.52±12.51)g/L,P=0.002]and higher serum ferritin[(225.08±103.36)μg/L vs.(155.19±115.38)μg/L,P=0.029],EPO[(41.28±12.58)IU/L vs.(28.38±10.52)IU/L,P＜0.001],and hepcidin[(48.03±34.44)μg/L vs.(27.42±15.00)μg/L,P=0.009]compared with periodontally healthy volunteers.After adjusting the age with the co-variance analysis,these parameters(hemoglobin,ferritin,EPO,and hepcidin)showed the same trends as independent-sample t test with statistical significance.Three months after periodontal initial therapy,all the periodontal parameters showed statistically significant improvement.The serum hemoglobin raised[(146.05±15.48)g/L vs.(133.77±13.15)g/L,P＜0.001],while the serum ferritin[(128.52± 90.95)μg/Lvs.(221.22±102.15)μg/L,P＜0.001],EPO[(27.66±19.67)IU/L vs.(39.63± 12.48)IU/L,P=0.004],and hepcidin[(32.54±18.67)μg/L vs.(48.18±36.74)μg/L,P=0.033]decreased compared with baseline.Conclusion:Tendency of iron metabolism disorder and ane-mia of inflammation was observed in patients with stage Ⅲ periodontitis,which can be attenuated by periodontal initial therapy.