The anti-inflammatory effect of Cirsium setidens (C. setidens) roots was evaluated for its potential to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW 264.7 cells. The ethanol (EtOH) extract of C. setidens exhibited strong anti-inflammatory activities in the NO production by LPS-stimulated RAW 264.7 cells. The individual fractions tested were, in order of most-to-least potent in anti-inflammatory activity: n-butanol (n-BuOH)>ethanol (EtOH)>water ($H_2O$)>ethyl acetate (EtOAc)>dichloromethane ($CH_2Cl_2$). The n-BuOH soluble fraction, which exhibited the strongest anti-inflammatory activity, was further purified by repeated MCI gel, silicagel, and RP-18 gel column chromatography. Syringin, isolated from C. setidens roots for the first time, were found to inhibit NO production in LPS-induced RAW 264.7 cells. High performance liquid chromatography (HPLC) was used for the analysis of the syringin in the EtOH extract of Cirsumn species.