The crude extract of Saussurea lappa displayed significant lethality to brine shrimp larvae. Investigation of the causative components by bioactivity-directed fractionation resulted in the isolation of three $C_17$-polyene alcohols. Based on various nmr spectral data, these compounds were identified as shikokiols which had been previously isolated from Cirsium nipponicum and/or Centaurea aegyptica. These $C_17$-polyene alcohols exhibited moderate cytotoxicities against the human tumor cell lines, A549, SK-OV-3, SK-MEL-2, XF498, and HCT15.