Abstract The chemical composition of the stem, leaf and flower oils from Pluchea rosea Godfrey and Pluchea purpurascens (Sw.) DC. were studied by GC and GC/MS. In P. rosea, 132 compounds were identified which constituted more than 87%, 92% and 89% of the oil composition in the stem, leaf and flower oils, respectively; while in P. purpurascens, 163 compounds were identified which constituted more than 89%, 95% and 95% of the oil composition in stems, leaves and flowers, respectively. The most prominent compounds in the oils from P. rosea were 2,5-dimethoxy-p-cymene (33.7% in stem oil) and selin-11-en-4α-ol (43.1% and 47.8% in leaf and flower oils, respectively); while in P. purpurascens, the major compounds were β-selinene (27.6%), selin-11-en-4α-ol (21.6%) and β-bourbonene (11.7%) in the stem oil; selin-11-en-4α-ol (24.6%), caryophyllene oxide (12.6%) and 2,5-dimethoxy-p-cymene (8.8%) in the leaf oil, and β-selinene (26.9%), β-caryophyllene (12.8%), α-cadinol (8.0%) and caryophyllene oxide (7.4%) in the flower oil.