The aerial parts of Ageratina adenophora (Spreng.) K. et R. afforded β-farnesene, germacrene D, bisabolene, caryophyllene and six further sesquiterpenes, the cadinene derivatives 1-6, of which only 1 had been isolated previously [1]. The structures of 2-6 followed from the ¹H NMR data (Table 1) and spin decoupling. We have named compound 4, without an oxygen function at C-9, ageraphorone. Cadinene derivatives have so far been isolated mainly from Chromolaena species [2,3], a genus not closely related to Ageratina.