Abstract: Essential oils from the leaves of three species of Clausena plants, namely Clausena dunniana Levl., Clausena lansium (Lour.) Skeels and Clausena lenis Drake were obtained by steam distillation. The chemical constituents of the oils were separated and identified by means of capillary gas chromatography-mass spectrometry. 38, 81 and 28 peaks were separated, respectively, of which 34, 62 and 19 compounds were identified, representing 99.64%, 92.85% and 94.40% of the total oil amount, respectively. The main components of the three essential oils are monoterpenoids, sesquiterpenoids, derivatives of phenol and aliphatics.

Key words: Clausena, essential oil, chemical constituents, GC-MS