the leaf essential oil compositions of four cinnamomum species from vietnam were analyzed by gas chromatography (gc) and gc-mass spectrometry (gc-ms). the main compounds of cinnamomum sericans hance were the sesquiterpenes spathulenol (14.5%), caryophyllene oxide (9.3%), -caryophyllene (7.1%) and bicyclocgermacrene (6.0%). the monoterpenes were represented by -pinene (9.3%) and sabinene (8.0%). however, monoterpenes were the dominant class of compounds in cinnamomum durifolium kosterm comprising mainly of -cymene (15.6%), limonene (13.9%) and -phellandrene (9.2%). spathulenol (7.4%) among the sesquiterpenoids and benzyl benzoate (6.5%), an aromatic ester were also present. the leaf oil of cinnamomum magnificum kosterm was devoid of monoterpene compounds, while the major sesquiterpenes were bicyclogermacrene (33.9%), -caryophyllene (25.5%), bicycloelemene (7.2%) and caryophyllene oxide (7.5%). -caryophyllene (35.9%), caryophyllene oxide (12.6%) and spathulenol (5.2%) were the dominant compounds of cinnamomum iners reinw. ex blume. the low content of (e)-cinnamaldehyde in the cinnamomum species is typical for majority of species already reported from vietnam.