The flowers of Pulicaria laciniata (Coss. et Kral.) Thell. (Asteraceae) afforded a new sesquiterpene acid 1, named lacitemzine together with the three known compounds, 4-hydroxy-3-methoxypyridine 2, b-sitosterol-3-O-b-D-glucoside 3 and 1,3,5-trimethoxybenzene 4. The structure of compound 1, 2-(2,6 dimethyl-3,4,5,6,7,8,9,10-octahydro-5,8-oxaazulen-9-yl)acrylic acid, contains a guaiane skeleton and was elucidated by spectroscopic procedures including 2D-NMR and X-ray diffraction.