The aerial parts of Artemisia argentea afforded, in addition to arborescin and argentiolides A and B, one new ketopelenolide derivative named deacetylargentiolide B and some previously unreported guaianolides. In continuation of our studies on the sesquiterpene lactones of Artemisia argentea [1], we report herein the isolation and characterization of another new naturally occurring sesquiterpene lactone designated as deacetylargentiolide B (5), which has been prepared previously by deacetylation of the natural compound argentiolide B (3). In addition to known sesquiterpene lactones 1, 3 and 6 [2], the lactones 2 and 4, as well as considerable amounts of artemetin, sesamin and lirioresinol-C-dimethyl ether, have been isolated. The structures of 2 and 4 followed from the 1H NMR spectra (Experimental), which were similar to that of arborescin [3, 4]. In agreement with the molecular formulae the structures 2 and 4 were proposed, which, however, may be artefacts formed by hydrolysis of the epoxide moiety in 1. A new trinortriterpenoid dilactone, deacetoxybrachycarpone, has been isolated from Cleome brachycarpa and its structure determined mainly by spectroscopic studies. Cabralealactone and ursolic acid were also isolated.