The roots of Launaea mucronata afforded, in addition to lactucin, lactucin-α-o-acetate and the corresponding dihydro derivative, 11β,13-dihydrolactucin. So far little is known of the chemistry of the genus Launaea, only some widespread triterpenes are reported [1]. The roots of L. mucronata Forssk. afforded lactucin (1) [2], the acetates 2 [3] and 4 [3] as well as the corresponding diol 3, not isolated previously. The structure followed from the molecular formula (C₁₅H₁₈O₅), the ¹H NMR spectral data (Table 1) and spin decoupling. Irradiation of a narrowly-split double quartet at δ 6.43 caused a sharpening of two broadened doublets at 4.86 and 4.53, which therefore were the signals of H-15, as the downfield shift of the former signal was typical for a H-3 proton of lactones like lactucin. Irradiation of the triplet at δ 3.65 collapsed the broadened doublet at 3.57 to a doublet and the three-fold doublet at 2.13 to a double doublet, thus allowing the assignment of the H-5 and H-7 signals. The latter was further coupled with a three-fold doublet at δ 3.75 and a double quartet at 2.57. Since the latter was coupled with the methyl doublet δ 1.44 and the signal at 3.75 with two double doublets at 2.71 and 2.32, all signals could be assigned. The coupling J indicated the α-orientation of the C-11 methyl group. Compound 3 therefore was 11β,13-dihydrolactucin. Consequently the ¹H NMR spectral data were close to those of the corresponding acetate isolated from a Lactuca species [3].