abstract the chemical composition of the oils obtained from the leaves of croton sonderianus from different regions of cear'a state (northeast of brazil) from the same population at different times were analyzed by gc/ms: -pinene, myrcene, 1,8-cineole, -caryophyllene and spathulenol. representative constituents present in almost all analyses were used for comparison. the oils from different plant parts (leaves, flowers, roots and trunk barks) of a same specimen were also analyzed: -phellandrene (20.4%, leaves), bicyclogermacrene (29.1% and 17.7%, flowers and leaves, respectively), -elemene (17.8% and 22.8%, flowers and trunk bark, respectively), cyperene (14.2%, roots) and germacrene d (12.8%, trunk bark) were the major components.