Objective To research the possible mechanism of Qi-Benefiting Phlegm-Eliminating Formula（ QBPEF） for lung cancer. Methods Fifteen BALB/c mice were selected to establish lung cancer xenografts models with human lung adenocarcinoma cell A549

and the mice were randomized into model group

QBPEF low-dose group and QBPEF high-dose groups

with 5 in each. The QBPEF low-dose and high-dose groups were given 27. 3 g /（ kg·d） or 54. 6g/（ kg·d） crude drug of QBPEF each day respectively from the 8th day after modeling for 2 consecutive weeks. The model group was given the same volume of normal saline. The morphological changes in transplanted tumor tissue were observed with HE staining and transmission electron microscopy. The expressions of GRP78 / BIP and caspase-12 were detected with immunohistochemistry and Western blotting. The pathological changes in major organs were observed with HE staining. Results The transplanted tumor cells showed a morphological change of apoptosis in QBPEF groups after treatment

especially in the QBPEF high-dose group. Comparing with the model group

the expression of GRP78 / BIP was significantly decreased but the expressions of caspase-12 and cleaved caspase-12 were significantly increased in QBPEF groups（ P < 0. 05 or P < 0. 01）

especially in the QBPEF highdose group（ P < 0. 01）. There was no obvious morphological change in major organs. Conclusion QBPEF can induce apoptosis in lung cancer cells with a dose-dependent manner

which may be related to activating caspase-12 and starting the endoplasmic reticulum stress apoptosis pathway.