Background; Immunological dysfunction plays a key role in the pathogenesis of inflammatory bowel disease (I B D). Notopterol is the main ingredient of the traditional Chinese herb medicine Notopterygium ineisum Ting ex H. T. Chang and has anti-inflammatory effect. Aims; To explore the effect of notopterol on dextran sulfate sodium (DSS)-induced colitis in mice. Methods; C57BL/6 mice were randomly divided into normal group, negative control group, model group and notopterol group. Mice in model group and notopterol group were treated with 2% DSS to induce colitis. Mice in negative control group and notopterol group were injected intraperitoneally with notopterol 40 mg/kg, and mice in normal group and model group were injected intraperitoneally with 0. 9% NaCl solution. Mice were sacrificed 10 days later, and disease activity index (DAI) score, colon length and histopathologieal score were determined. The levels of TNF-α, IL-1β, IL-6, IL-17A were assessed by ELISA. The mRNA expressions of IL-17A, RORγt were detected by quantitative PCR. Results; Compared with the normal group, DAI score, histopathologieal score, levels of TNF-α, IL-1β, IL-6, IL-17A, mRNA expressions of IL-17A and RORγt in model group were significantly increased (P < 0. 0 1), and colon length were significantly shortened (P < 0. 0 1). Compared with the model group, notopterol significantly reduced DAI score and histopathologieal score (P<0.01), downregulated levels of TNF-α, IL-1β, IL-6, IL-17A (P<0.01), inhibited the mRNA expressions of IL-17A, ROR-γt (P < 0. 0 1), and greatly recovered colon length (P < 0. 0 1). Conclusions; Notopterol has protective effects on DSS-induced colitis in mice. The mechanism may be related to reducing the secretion of pro-inflammatory cytokines and inhibiting the function and differentiation of Thl7 cells.