The bark of Croton malambo and the aerial parts of Croton cuneatus were subjected to hydrodistillation to obtain the essential oils of each specie. The composition of these samples were analysed by GC-MS and by NMR. The analysis of the C. malambo oil showed 36 constituents including traces, in which methyl eugenol (65.4%), methyll isoeugenol (6.3%), elemicine (4.7%), isoelemicine (3.4%), veratral (3.0%) and delta-cadinol (4.1%) were the major components. C. cuneatus oil was found to be rich in phenylpropanoids and sesquiterpene alcohols, showing 43 compounds, where alpha-11eudesmene (51.3%), methyleugenol (25.9%), 4-alpha-seleniol (10.2%), cedryl propyl ether (2.9%), tau-cadinol (4.4%), cubenol (1.3%) methyl isoeugenol (1.2%), veratral (1.3%) and agarospirol (1.0%) were the most abundant compounds. Copyright (c) 2005 John Wiley & Sons, Ltd.