Five terpenes (1-5), three fatty acids (6-8), two sterols (9 and 11), and a monogalactosyldiacyl glycerol (10) were isolated from the methylene chloride extract of the aerial part of Cirsium setidens. Their chemical structures were determined to be alpha-tocopherol (1), 25-hydroperoxycycloart-23-en-3beta-ol (2), 24-hydroperoxycycloart-25-en-3beta-ol (3), mokko lactone (4), transphytol (5), 9,12,15-octadecatrienoic acid (6), 9,12-octadecadienoic acid (7), hexadecanoic acid (8), acylglycosyl beta-sitosterol (9), (2R)-1,2-O-(9z,12z,15z-dioctadecatrienoyl)-3-O-beta-D-galactopyranosyl glycerol (10) and beta-sitosterol glucoside (11) by spectral evidences. Compound 3 exhibited significant cytotoxic activity against five human cancer cell lines with its ED50 values ranging from 2.66 to 11.25 microM.