The eudesmane sesquiterpenoids 1-3 and the trans-chrysanthemyl monoterpenoid 4 have been isolated from the aerial parts of Santolina insularis, a bush endemic to Sardinia. The absolute stereostructures of these novel compounds and of two known but incompletely characterized chrysanthemanes (5, 6) were established by spectroscopic techniques and by application of the modified Mosher method. The presence of the p-menthane aldehyde eucamalol (7) gives credit to the widespread use of S. insularis to fend off mosquitoes.