Abstract： Objective To investigate the clinical results of non-surgical periodontal treatment of generalized aggressive periodontitis in a Chinese population.Methods Nineteen patients aged(24.5±4.1)years with generalized aggressive periodontitis were included in this prospective study.All subjects received scaling and root planing and were clinically monitored every 2 months for 6 months.The clinical parameters,including probing depth(PD),bleeding on probing(BOP),attachment loss(AL)and mobility,furcation involvement of molars were recorded at baseline,2,4 and 6 months after treatment.White blood cells,neutrophil percentage,triglyceride of 7 patients were detected at baseline and 6 months after treatment.Results At baseline,the mean PD of patients was(5.1±2.1)mm,the percentage of BOP positive sites was 98.0% and mean AL was(3.9±1.9)mm.At 6 months after treatment,the mean pocket depth reduction was 2.0 mm,the percentage of BOP positive sites reduced to 11.9% and 0.6 mm attachment level was gained.Incisors showed greater PD reduction than molars,the baseline PD had predictive effect on PD reduction,deep sites showed greater PD reduction than shallow sites.There was a statistically significant decrease of neutrophil percentage at 6 months after treatment[(65.7±9.9)% vs.(55.4±9.3)%,P<0.05].Conclusions Non-surgical treatment is effective for the generalized aggressive pefiodontitis and every 2 months SPT is necessary for maintenance.Further surgical treatment or repeated SRP is recommended for molars.