<p><b>OBJECTIVE</b>To investigate the expression of Th1/Th2 transcription factors and cytokines in peripheral blood of patients with esophageal squamous cell carcinoma (ESCC) during radiotherapy to provide an evidence for using traditional Chinese medicine in anti-tumor immunotherapy.</p><p><b>METHODS</b>Sixty patients with ESCC undergoing radiotherapy were randomly and equally assigned to the tested group (treated with combined treatment of Aidi Injection) and the control group (treated with radiotherapy alone). A group consisted of 20 healthy persons was set up meanwhile as the normal control. Patients' expressions of Th1 and Th2 type transcription factors and cytokines were detected before and after radiotherapy, the expression of T-bet and GATA-3 in peripheral blood monoclear cells (PBMCs) were detected by Real-time quantitative PCR (RT-PCR), and plasma expressions of interferon gamma (IFN-gamma), interleukin 2, 4 and 10 (IL-2, IL-4, IL-10) were detected by enzyme-linked immunosorbent assay (ELISA).</p><p><b>RESULTS</b>Compared with the healthy control group, the expressions of Th1 type transcription factor T-bet and cytokines IFN-gamma, IL-2 in ESCC patients were significantly lower (P < 0.01), while expressions of Th2 type transcription factor GATA-3 and cytokines IL-4, IL-10 were significantly higher (P < 0.01). These changes were exacerbated significantly after radiotherapy in the control group (P < 0.01), but only showed a slight change in the tested group with statistical insignificance (P > 0.05).</p><p><b>CONCLUSIONS</b>Radiotherapy can not reverse the Th1/Th2 shift presented in ESCC patients, while the combined intravenous dripping of Aidi Injection during radiotherapy can inhibit it effectively. The combined therapy could elevate the immune function in organism, enhance the radiosensitivity, and attenuate the toxic-adverse effect of radiotherapy.</p>