Objective To observe the clinical efficacy and safety of Compound Zhuye Shigao Granule（ 复方竹叶石膏颗粒） in treating recurrent oral ulcer. Methods One hundred recurrent oral ulcer patients were randomly divided into treatment group and control group

with 50 cases in each group. The treatment group was given Compound Zhuye Shigao Granule orally

12 g each time

three times a day. The control group was given Kouyanqing Granules（ 口炎清颗粒） orally

6 g each time

twice a day. The two groups were both treated for 7 days or 14 days. Visual analogue scale（ VAS） scores and the average periods of ulcers were observed before and after treatment

and the short term efficacy was evaluated. After treatment

telephone follow-up was conducted once a month to record whether the ulcer relapsed or not. If the ulcer relapsed

total interval time and the number of the ulcers were recorded

and telephone follow-up was continuously conducted for 6 months to evaluate the long term efficacy. Results There were49 cases included in the treatment group

and 48 cases in the control group. The total effective rate of the short term efficacy in the treatment group was 87. 8%

which was higher than that in the control group（ 70. 8%

P < 0. 05）.Relapse rate after 6 months in the treatment group was 34. 7%

and the total effective rate of the long term efficacy was 91. 8%. The efficacy was superior to that in control group. Relapse rate after 6 months in control group was60. 4%

and the total long term effective rate was 77. 1%（ P < 0. 05）. After treatment

the average periods of ulcers in both groups was shortened

VAS scores decreased obviously

the total time interval extended

the number of ulcer decreased

and the efficacy in treatment group was superior to that in control group（ P < 0. 05）. There was no adverse reaction during treatment. Conclusion Compound Zhuye Shigao Granule might promote recurrent oral ulcer healing and relieve pain. Compound Zhuye Shigao Granule seems superior to Kouyanqing Granules in the short and long term efficacy

and it seems to have good safety.