abstract the essential oil of the leaves of six samples of piper aduncum l. growing wild in two different region of pernambuco, northeast of brazil (brejo da madre de deus-samples bmd1-3 and serra negra-samples sn1-3), were investigated by a combinations of gc and gc/m s. the characterized oil samples from different localities show a high percentage of oxygen-containing sesquiterpenes in both places (bmd1-3: 90.1-90.8% and sn1-3: 95.6-97.5%). oxygen-containing monoterpenes represented less than 6% in bmd1-3 and less than 1% in sn1-3. twelve compounds were identified representing more than 95% of each of the oil samples. (e)-nerolidol was found to be the main component in all the samples being present in bmd1-three in the range of 81.5 to 82.5% while in sn 1-3 79.2-81.2% were found. despite the fact that some minor components are not present in each oil sample, this investigation showed the same compositions of the major components of the essential oils of these p. aduncum from different region of pernanambuco. longipinanol (bmd1-3: 2.4-5.6%; sn1-3: 11.1-13.6%) and epi-logipinanol (bmd1-3: 2.1-2.2%; sn1-3: 2.2-0.3%) are unusual components present in the samples, which could be identified for the first time in the p. aduncum species.