To observe the clinical efficacy，recurrence rate and serum inflammation of patients with recurrent oral ulcer treated by Kouyanqing Granules（口炎清颗粒）combined with Kangfuxin Liquid（康复新液）.

Sixty patients with mild recurrent oral ulcer treated in the stomatology department of the hospital from January 2020 to September 2022 were selected as the research objects. The patients were divided into conventional treatment group and Kouyanqing Granules group by random number table method，with 30 cases in each group. The conventional treatment group was given Kangfuxin Liquid. The Kouyanqing Granules group was orally treated with Kouyanqing Granules on the basis of conventional treatment group. The clinical efficacy，clinical symptoms，recurrence rate and adverse reactions of the two groups were compared as well as the changes of serum inflammatory factors and immune function before and after intervention.

The effective rate of the conventional treatment group was 73.33%（22/30）and that of Kouyanqing Granules group was 93.33%（28/30）. Compared with the conventional treatment group，the effective rate of the Kouyanqing Granules group was significantly increased（P<0.05）. Compared with those of the conventional treatment group，the pain duration，wound healing time and feeding improvement time in the Kouyanqing Granules group were significantly shortened and the differences were statistically significant（P<0.01，P<0.05）. After the intervention，the levels of CD3⁺，CD4⁺and CD4⁺/CD8⁺in peripheral blood of the Kouyanqing Granules group were significantly higher than those of the conventional treatment group，while the levels of CD8⁺were significantly decreased（P<0.01，P<0.05）. After the intervention，the serum levels of IL-1，IL-6 and TNF-αin the Kouyanqing Granules group were significantly decreased compared with those in the conventional treatment group（P<0.01）. There was no significant difference in recurrence rate between the two groups at 3 and 6 months after the intervention（P>0.05）. However，compared with those of the conventional treatment group，the total recurrence rate of the Kouyanqing Granules group was significantly reduced（P<0.05）. No obvious drug-related adverse reactions or allergic reactions occurred in the two groups during the intervention.

Kouyanqing Granules combined with Kangfuxin Liquid have good clinical effects in the treatment of recurrent oral ulcer，which can significantly improve the clinical symptoms of patients and reduce the recurrence rate. Its mechanism of action is related to inhibiting serum inflammatory response and regulating the body's immune function.