abstract essential oils from leaves, stems and roots of plectranthus barbatus andr.(labiatae) were analyzed by gc/ms. the major constituents found were -pinene (22.2%) in the leaves, -phellandrene (26.1%) in the stems, and (z)--ocimene (37.6%) in the roots. although diterpenes were reported previously in this species, this is the first time that manool (1.0%) and abietatriene (0.7%) have been found in the leaf, and roots oils, respectively.