From the chloroform extract of decoctum of Laggera Pterodonta (DC) Benth (Compositae) aried part, Compound 1-4 were obtained after colum chromatography on silical gel and crystallization. 1 is a new compound which has sesquiterpene skeleton of eudesmane based on ^1^3C NMR, ^1H-^1H cosy and mass spectral data. It has the structure of Δ ^4^,^1^1-eudesm-dien-3-one-13-oic acid. 2-4 were elucidated as the known ilicic acid, artemitin and chrysospeneti B respectively based on the spectroscopic data and comparision with the literature.

Key words: CHEMICAL COMPOSITION, ULTRAVIOLET SPECTROPHOTOMETRY, FLAVONOID, SESQUITERPENE, INFRARED SPECTROPHOTOMETRY, NUCLEAR MAGNETIC RESONANCE, MASS SPECTROGRAPHY