The purpose of this study is to compare the constituent contents of essential oils from the leaves of Melaleuca leucadendra (ML) that were collected in Taiwan. Four essential oils were obtained from ML with four extraction methods, including water distillation, steam distillation, CO2 supercritical fluid extraction and n-hexane extraction. They were calculated the extract yields, respectively, and then were analyzed by GCMSMS to compare their constituents contents, ine results srsnowed that the highest extract yield was C02 supercritical fluid extraction (4.11%), the lowest extract yield was water distillation (1.05%). Eucalyptol was found in four essential oils. Steam distillation exniDited the highest content of eucalyptol, 57.94%,and -hexane exuaction method had the least of eucalyptol, 4.06%. Other constituents such as limonene,p-menth-l-en-8-ol, viridiflorol and nerolidol were also found in four essentiaial oils. Our study results demonstrated that using different extractions to obtain various essential oils had significant differences in constituent contents.
