Objective To observe the effect of Liujunzi Decoction（ LD

六君子汤） on dendritic cells in esophageal microenvironment and explore the potential mechanism. Methods Peripheral blood mononuclear cells were isolated by Fieoll density gradient centrifugation and cultured in vitro

and then the dendritic cells were induced. The dendritic cells were divided into a normal culture medium group（ normal culture）

a tumor culture medium group（ 30% esophageal cancer EC-9706 cell culture supernatant）

and a LD group（ 30% LD intervened esophageal cancer EC-9706 cell line culture supernatant）. Seven days later

dendritic cell surface markers CD80

CD86 and CD1 a in these three groups were detected by flow cytometry. The proliferation of lymphocytes was detected by MTT assay and the stimulation index was calculated. LDH release assay was used to detect the lethality of cytotoxic T lymphocyte（ CTL） to calculate the specific killing rate. The content of interleukin-12（ IL-12） was detected by ELISA

and the expressions of STAT3 and p-STAT3 proteins by Western blot. Results Compared with those in the normal medium group

levels of CD80

CD86 and CD1 a decreased

the stimulation index and CTL specific killing rate decreased

the content of IL-12 decreased and the expressions of STAT3 and p-STAT3 increased in the tumor culture medium group（ P < 0. 05）. Compared with those in the tumor culture medium group

levels of CD80

CD86 and CD1 a increased

the stimulation index and CTL specific killing rate increased

the secretion of IL-12 increased

and the expressions of STAT3 and p-STAT3 decreased in LD group（ P < 0. 05）. Conclusion LD could change the maturation and immunological activity of dendritic cells by affecting the microenvironment of esophageal cancer cells

which may be related to the regulation of STAT3 signaling pathway.