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-4-ol (43.1% and 47.8% in leaf and flower oils, respectively); while in p. purpurascens, the major compounds were -selinene (27.6%), selin-11-en-4-ol (21.6%) and -bourbonene (11.7%) in the stem oil; selin-11-en-4-ol (24.6%), caryophyllene oxide (12.6%) and 2,5-dimethoxy-p-cymene (8.8%) in the leaf oil, and -selinene (26.9%), -caryophyllene (12.8%), -cadinol (8.0%) and caryophyllene oxide (7.4%) in the flower oil.