Objective: To study the immune protective mechanism of Qingying Jiebiao Heji on A/PR/8/H1N1 virus infected mice. Method: The influenza model in mice was established through dropping A/PR/8/H1N1 virus into the nose of Kunming mice. Ribavirin and Qingying Jiebiao Heji were given to the infected mice respectively

then death protection and life prolongation were determined; thymus index and spleen index were observed; Th1(IFN-γ)/Th2(IL-10) expression in peripheral blood was measured by flow cytometry. Result: After being infected

the death protection rate and life prolongation rate of Qingying Jiebiao Heji were 52.94% and 37.64% accordingly

the thymus index and spleen index were improved apparently. Th1 cytokine IFN-γ attenuated and Th2 cytokine IL-10 dominantly expressed. The expression of Th1 (IFN-γ)/Th2 (IL-10) was remarkably depressed and adjusted

Th2 expression of Qingying Jiebiao Heji group was markedly strengthened and Th1 / Th2 drifted towards the normal level. Conclusion: Qingying Jiebiao Heji has the effect of death protection on the A/PR/8/H1N1 virus infected mice

it also can reverse its peripheral blood cytokine Th1 drifting to Th2

and prevent influenza through immune regulation.