To investigate the clinical effect of Yiqi Jiedu Granule combined with ganciclovir on herpes simplex keratitis (HSK) and its influence on T lymphocyte subsets. Methods:A total of 148 patients with HSK admitted to Ningde Hospital were selected as the research objects and were randomly divided into a control group and an experimental group according to random number table, with 74 cases in each group. The control group received ganciclovir, while the observation group received Yiqi Jiedu Granule on the basis of the control group. Both groups were treated continuously for 4 weeks. The treatment effects of the 2 groups, the ratio of T lymphocyte subsets in the peripheral blood and the levels of inflammatory factors in the 2 groups before and after treatment were compared; the regular follow-up for 6 months after the treatment was performed, and the recurrence of the 2 groups was counted. Results:The total effective rate of experimental group was 98.65%, which was higher than that of ganciclovir group (87.84%, P<0.05). After treatment, the ratio of CD4+ cells and CD4+/CD8+ cells in the observation group increased (P<0.01), while the ratio of CD8+ cells decreased than that before treatment (P<0.01), with significant difference between the 2 groups (P<0.01). After treatment, the levels of interleukin-18 (IL-18) and interferon-γ (IFN-γ) increased in both groups (P<0.05 or P<0.01). And the observation group was higher than the control group (P<0.01). The recurrence rate of experimental group was 14.29%, which was lower than that of the ganciclovir group (45.46%, P<0.05). Conclusion:The clinical effect of ganciclovir combined with Yiqi Jiedu Granule in the treatment of HSK is more obvious, which can reduce the level of inflammatory factors in vivo and improve the cellular immune function of patients with low recurrence rate and remarkable curative effect.