Objective To investigate the cytokines levels in peripheral blood of ulcerative colitis (UC) patients at active stage, and to observe the effect of baicalin at various concentrations on the cytokines. Methods Quantitative polymerase chain reaction (Q-PCR) assay was used for the detection of interleukin 4 receptor (IL4R), IL6R, IL23R and RAR-related orphan receptor C (RORC) expression in single peripheral mononuclear cell of UC patients. Enzyme-linked immunosorbent assay (ELISA) was used to examine the serum levels of interferon gamma (IFN-γ), IL-4, IL-5, IL-6, IL-10, and transforming growth factor beta (TGF-β) levels in UC patients, and was applied for in-vitro detection of these indicators after baicalin intervention. Results Q-PCR results showed that IL4R, IL6R, IL23R, RORC gene expression levels in UC patients were increased to various degrees as compared to diarrhea-predominant irritable bowel syndrome (IBS-D) patients and the healthy volunteers, and then the levels were decreased to various degrees after intervention by baicalin at different concentrations, in particular at 20 and 40μmol/L. The results of ELISA showed that serum levels of cytokines of IFN-γ, IL-5, IL-6 in UC patients were increased to various degrees while IL-4, IL-10 and TGF-β1 was decreased as compared to IBS-D patients and the healthy volunteers. Baicalin at the concentrations of 20 and 40 μmol/L had an effect on decreasing IFN-γ, IL-5, IL-6 and on increasing IL-4 and IL-10. Conclusion Higher concentrations of baicalin show obvious effect on inhibiting RORC and IL23R expression, on decreasing IFN-γ, IL-5, IL-6 levels, and on increasing IL-4, IL-10 and TGF-β1 levels, which indicated that the therapeutic mechanism of baicalin in relieving ulcerative colonic inflammation is related with the regulation of immune function.