OBJECTIVE： To observe therapeutic efficacy and safety of Kouyanqing granules for chronic periodontitis and it effects on inflammatory cytokine. METHODS： 110 patients with chronic periodontitis were divided into control group （55 cases） and observation group （55 cases）. Control group accepted the periodontal basic treatment as oral hygiene instruction， supragingival scaling， subgingival scaling and root planning. Observation group was additionally given Kouyanqing granules 20 g orally， twice a day， on the basis of control group. Both groups were treated for 4 weeks. Clinical efficacies of 2 groups were observed as well as the levels of plaque index（PLI），gingival index （GI）， probing depth（PD）， clinical attachment level（CAL）， IL-17，IL-21， and the occurrence of ADR. RESULTS： Both groups completed the treatment， and no patient lost to follow up. Total response rate of observation group was significantly higher than that of control group， with statistical significance （P＜0.05）. After treatment， the levels of PLI，GI， PD， CAL， IL-17 and IL-21 in 2 groups were significantly lower than before， and the observation group was significantly lower than the control group， with statistical significance （P＜0.05）. There was no statistical significance in the incidence of ADR between 2 groups （P＞0.05）. CONCLUSIONS： Based on routine treatment， Kouyanqing granules show significant therapeutic efficacy for chronic periodontitis， can significantly improve periodontal symptom and reduce inflammatory factor level， but do not increase the incidence of ADR.