Abstract：Objective：To observe the clinical effect of the therapy of ultrasonic subgingival scaling and gargle with modified Huanglian Jiedu Decoction on chronic periodontitis with intense heat toxin syndrome. Methods：A total of 104 cases of patients with chronic periodontitis with intense heat toxin syndrome were selected and divided into the control group and the observation group according to the random number table method， with 52 cases in each group. With two cases being culled in the control group， finally 52 and 50 cases were included into the observation group and the control group respectively. The two groups were given supragingival scaling and polishing ， and ultrasonic subgingival scaling after seven days. The control group was given gardling with 0.9% Sodium Chloride Solution，and the observation group was given gardling with modified Huanglian Jiedu Decoction. The clinical effects， levels of periodontal indexes [periodontal probing depth (PD)， gingival index (GI)， periodontal bleeding index (BI)， and plaque index (PLI)]，and inflammatory factors [interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α)] and oxidative stress indexes [malondialdehyde (MDA)， superoxide dismutase (SOD)， glutathione peroxidase (GSH-Px) and nitric oxide (NO)] in gingival crevicular fluid were compared between the two groups. Results：After one month of treatment，the total clinical effective rate was 98.08% in the observation group，higher than that of 84.00% in the control group (P＜0.05). The levels of PD， GI， BI， and PLI in the two groups were decreased when compared with those before treatment，and the above four levels in the observation group were lower than those in the control group (P＜0.05). The levels of IL-1β and TNF- α in gingival crevicular fluid in the two groups were decreased when compared with those before treatment (P＜0.05)， and the above two levels in the observation group were lower than those in the control group (P＜0.05). The levels of MDA and NO in gingival crevicular fluid in the two groups were decreased when compared with those before treatment (P＜0.05)，and the levels of SOD and GSH-Px in gingival crevicular fluid were increased when compared with those before treatment (P＜0.05)； the levels of MDA and NO in gingival crevicular fluid in the observation group were lower than those in the control group (P＜0.05)，and the levels of SOD and GSH-Px in gingival crevicular fluid in the observation group were higher than those in the control group (P＜0.05). Conclusion： Ultrasonic subgingival scaling and gargle with modified Huanglian Jiedu Decoction can effectively improve the periodontal symptoms of patients with chronic periodontitis with intense heat toxin syndrome. The action mechanism may be related to inhibiting periodontal tissue inflammation and improving oxidative stress responses in periodontal tissue.