Abstract： Objective： To observe the clinical effect of modified Shimu Jiangyan Decoction on chronic periodontitis with intense stomach fire syndrome. Methods： A total of 78 cases of patients with chronic periodontitis were selected and divided into the control group and the observation group according to the random number table method， with 39 cases in each group. The two groups were given conventional measures such as health education， plaque control， and gingival scaling. The control group was treated with conventional western medicine， and the observation group was additionally treated with modified Shimu Jiangyan Decoction based on the treatment of the control group. Both groups were treated for four weeks. Clinical effects in the two groups were evaluated. Scores of main symptom indicators of periodontitis， indicators of breath odor， improvement time of symptoms and signs， and levels of matrix metalloproteinase (MMP)-2，MMP-9，and tissue inhibitor of metalloproteinase-2 (TIMP-2) in the gingival crevicular fluid were compared between the two groups. Results：After four weeks of treatment courses， the total effective rate was 94.87% in the observation group，which was higher than that of 74.36% in the control group (P＜0.05). After treatment， scores of plaque index， gingival index， probe depth， and gingival sulcus bleeding index in the two groups were decreased when compared with those before treatment (P＜0.05)，and each score in the observation group was lower than that in the control group (P＜ 0.05). After treatment， levels of oral volatile compounds (VSCs) and organoleptic score (OS) in the two groups were declined when compared with those before treatment (P＜0.05)，and the levels of VSCs and OS in the observation group were lower than those in the control group (P＜0.05). The disappearance time of loose teeth，bad breath，and gum swelling and pain in the observation group was shorter than that in the control group (P＜0.05). After treatment， levels of MMP-2 and MMP-9 in gingival crevicular fluid in the two groups were reduced when compared with those before treatment (P＜0.05)， and the levels of TIMP-2 in the observation group were increased when compared with those before treatment (P＜0.05)； the levels of MMP-2 and MMP-9 in the observation group were lower than those in the control group，and TIMP-2 level in the observation group was higher than that in the control group (P＜0.05). Conclusion： Modified Shimu Jiangyan Decoction has a significant clinical effect in the treatment of chronic periodontitis with intense stomach fire syndrome， which can improve symptom indicators related to periodontitis and regulate levels of MMP-2，MMP-9，and TIMP-2.