In addition to the already described peruvin (I), two further lactones, 3α-hydroxy-11αH,13-dihydrodamsin (II) and, 3α-acetoxy-11αH,13-dihydrodamsin (III), were isolated from aerial parts of species Ambrosia artemisiifolia L. The full structure of these lactones was derived from their NMR and CD spectra and the X-ray structural analysis of compound III. In the aerial part of Ambrosia trifida L. species coronopilin (V) and ivoxanthin (VI) were also identified.