The aerial parts of Lactuca sativa afforded lactucin, 11β,13-dihydrolactucin, lactupicrin, a new melampolide and 3β,14-dihydroxy-11β,13-dihydrocostunolide. From the aerial parts of wild growing Lactuca sativa L., which is cultivated as a vegetable throughout Europe, so far only triterpenes have been reported [1]. We now have studied again this species. In addition to the triterpenes (see Experimental), lactucin [2,3], lactupicrin [3,4] and 11β,13-dihydrolactucin [5], two further sesquiterpene lactones were obtained (1 and 2). From the molecular ion of 1 the molecular formula C15H20O4 was deduced. The IR spectrum exhibited bands typical for hydroxyl (3600), γ-lactone (1770) and conjugated aldehyde groups (2730, 2690, 1630 cm⁻¹). The structure was elucidated from the ¹H NMR spectrum (Table 1). The presence of an 11β,13-dihydro derivative of a methylene lactone followed from the methyl doublet at δ 1.15 and double quartet at δ 2.18. The coupling of 12 Hz indicated an 11β-proton. Spin decoupling starting with the signal at δ 2.18 allowed the assignment of the whole sequence as H-1 showed an allylic coupling with H-9β. The chemical shift of H-14 required Δ¹(10) double bond with the E-configuration and the coupling of H-3 agreed with the presence of a 3β-hydroxy derivative. Thus the structure and the stereochemistry of the lactone was established as 1, 3β-hydroxy-11β,13-dihydroacanthospermolide. It is closely related to an isomeric melampolide with an 8β-hydroxyl group instead of the 3β-hydroxyl which was isolated from Blainvillea species [6]. Also urospermal A [7] from Urospermum species which is in the same tribe as Lactuca, is an acanthospermolide derivative. The structure of 2, molecular formula C15H22O3, also followed from the ¹H NMR spectrum (Table 1). All signals could be assigned by spin decoupling. As the broadened doublet at δ 4.76 was coupled both with H-6 and H-15 the relative position of the secondary hydroxyl group was settled. Similarly the fact that the threefold doublet at δ 2.32 was coupled with H-1 and the lowfield double doublet at δ 4.30 indicated a secondary hydroxyl group at C-3. The configuration at C-3 and C-11 followed from the couplings. Compounds 1 and 2 are closely related. As in other cases the presence of a 14-carbonyl group induces an isomerization of the 1(10) double bond. The chemistry of this species again shows that 11β,13-dihydro derivatives of sesquiterpene lactones are common in the tribe Cichorieae. The aerial parts of Viguiera gilliesii afforded five heliangolides and one new acyclic diterpene, (E, Z, Z)-3,7,11-trihydroxymethyl-15-methyl-2,6,10,14-hexadecatetraen-1-ol. Structures were elucidated by spectroscopic methods and by comparison of the data with those of closely related compounds. As part of a general phytochemical investigation of the native vegetation of the Cuyo Region (Argentina), we have studied Viguiera gilliesii Hook et Arn collected in Villavicencio (Mendoza). Reports on about 25 Viguiera species have appeared so far. Furanoheliangolides and heliangolides as well as diterpenes are characteristic constituents but germacradienolides have also been found.