To observe the clinical curative effect of the treatment of Lanqin oral liquid on infantile hand foot mouth disease(HFMD),and analyze its mechanism.Methods:During March 2015-December 2016,86 pediatric patients with HFMD were randomly divided into control group and treatment group,43 cases each, two groups of patients were symptomatic treatment, the control group with intravenous acyclovir treatment, and in the treatment group, the control group on the basis of Lanqin oral liquid in the treatment of. At the same time, 30 healthy children were selected as the healthy control group.The hs-CRP, Th1 and Th2 cells,CD3+,and CD19+ were measured before and after treatment in each group. The time of fever, the time of disappearance of herpes, the average length of stay and the clinical efficacy were evaluated.Results:After treatment,the total efficiency of treatment group was 95.35%,control group total effective rate was 79.07%(P<0.05),the treatment group in the symptom improvement time(the time of fever, herpes disappear time and average hospitalization time) was significantly less than the control group(P<0.05),while the hs-CRP,CD3+,CD19+ Th1 and the percentage of Th2 cells after treatment were improved, and the treatment group was significantly better than the control group(P<0.05).Conclusion:Lanqin oral liquid can improve the prognosis of children with hand, foot and mouth disease,improve the immune system of children, can significantly shorten the length of stay, improve the clinical efficacy,enhance the immune function of children,it is worth popularizing.