In summary, our experimental results show that thalidomide can dose-dependently reduce the DAI, CMDI, and TDI scores of TNBS-induced colitis in rats, possibly via downregulation of the expression of the cytokines IL-6, IL-17, and IL-23, and the transcription factor, RORγt, inhibiting the differentiation and power of Th17 cells and alleviating the inflammatory reaction in the intestinal tract. The gene discussed is IL6; the disease is colitis.