The extract of the leaves of Jasonia candicans yielded seven new sesquiterpenes and sesquiterpene lactones including a eudesmane containing a rare type of 6/6/4 membered ring system, two 7-epi-eudesmanes (12-hydroxyisointermedeol and 7-epi-ilicic acid), two guaianolides (inuviscolide and its 8-epi- derivative), iphionane and cadinane-triol derivatives. The structures were elucidated by spectroscopic analysis particularly high-resolution 1D and 2D NMR spectroscopy and the extensive NOE analysis.