AIM: To investigate the antiviral efficacy and mechanism of Qingre Xiaoyanning (QRXYN) in vivo, and provide experimental basis for their prevention and treatment of influenza A virus. METHODS: We constructed a mouse model infected with influenza A H3N2 virus. To evaluate the therapeutic effect of QRXYN on influenza A virus, we measured the body weight changes, pathological changes in lung tissue, hemagglutination titer, and viral load in mouse. To evaluate the possible mechanism of QRXYN's anti influenza A virus infection, we used the ELISA to measure the levels of TNF-α, IL-1β, IL-4, IFN-γ, and vascular cell adhesion molecule-1 (VCAM-1) in mouse bronchoalveolar lavage fluid; used flow cytometry to assess the proportions of macrophages (F4/80), helper T lymphocytes (CD4+ T lymphocytes), and natural killer (NK) cells in lung tissue; and used Western blotting to detect the expression of Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MYD88), inhibitor of kappa B kinase-β (IKK-β), NF-kappa-B inhibitor alpha (IκBα), and phospho-IKB alpha (p-IκBα) in lung tissue. RESULTS: Compared to the model group, both Oseltamivir and QRXYN can alleviate the severity of lung tissue lesions in mice, decrease the blood coagulation titer and viral load of mouse lung tissue (P<0.01), lower the levels of TNF-α, IL-4, and VCAM-1 in bronchoalveolar lavage fluid (P<0.05, P<0.01), reduce the proportion of macrophages (P<0.05, P<0.01), and increase the proportion of CD4+T lymphocytes and NK cells (P<0.05, P<0.01). Additionally, oseltamivir can reduce the expression of MYD88 protein in mouse lungs (P<0.05), while QRXYN can decrease the expression of IKK-β and P-IκBα proteins in mouse lungs (P<0.05). CONCLUSION: QRXYN have good in vivo antiviral effects against the influenza A virus, and their mechanism may be related to the regulation of the immunologic function and NF-κB signal pathway.