Abstract Essential oils from leaves, stems and roots of Plectranthus barbatus Andr.(Labiatae) were analyzed by GC/MS. The major constituents found were Î±-pinene (22.2%) in the leaves, Î²-phellandrene (26.1%) in the stems, and (Z)-Î²-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.