Objective: To explore the pro-apoptosis effects of Qiyu Sanlong decoction (QYSL) and its biological immunoregulation effect on Helper T cells in mice with lung cancer. Method: The mice models of lung cancer were established in C57BL/6 mice using lewis lung carcinoma cells line (LLC) by culture and transplantation method. After successful modeling

the mice were randomly divided into model group

chemotherapy group

QYSL group and combination group

8 cases in each group

another 8 cases normal mice were used as blank group. The survival state of mice was observed

the tumor was weighed and tumor inhibition rate was calculated. Transmission electron microscope was used to observe the ultrastructural changes of tumor cells and determine whether QYSL can induce apoptosis of tumor cells. Enzyme-linked immunosorbent assay (ELISA) was used to measure the levels of interleukin (IL)-2

interferon (IFN)-γ

IL-4 and IL-10 in the spleen of mice. The transcriptional level of Bcl-2 and Bax mRNA expressions in tumor tissues was detected by Real-time PCR assay. Result: The survival state of QYSL group and combination group was significantly superior to that of chemotherapy group. As compared with the model group

tumor growth could be significantly inhibited by QYSL group

chemotherapy group and combination group

with significant differences (P < 0.01). Under electron microscope

the tumor cells change was mainly based on apoptosis and necrosis was also present in QYSL group

multiple apoptotic bodies were visible

typical necrotic cells were visible in combination group. Expression level of Bcl-2 mRNA in various treatment group was significantly lower than that in model group (P < 0.01). Bcl-2 mRNA expression level in QYSL group and combination group was lower than that in chemotherapy group (P < 0.01). Expression of Bax mRNA in treatment groups was significantly higher than that in model group

and the expression of Bax mRNA in combination group was increased as compared with the chemotherapy group. As compared with the model group and chemotherapy group

the IL-2 level in QYSL group and IFN-γ level in combination group were increased (P < 0.01). The IL-4 and IL-10 levels in QYSL group and combination group were lower than those in model group (P < 0.05)

while above two levels in combination group were significantly lower than those in chemotherapy group (P < 0.01). Conclusion: Qiyu Sanlong decoction can improve the survival state and induce apoptosis of lung cancer cells in mice with lung cancer

and the apoptosis mechanism may be related to the down-regulation of Bcl-2 level and up-regulation of Bax level. Qiyu Sanlong decoction can also improve the immune function and inhibit the tumor immune escape by increasing IL-2

IFN-γ levels and decreasing IL-4

IL-10 levels to balance Th1/Th2 drift.