abstract essential oil was isolated from the leaves of plectranthus amboinicus by hydrodistillation and analyzed using both gas chromatography (gc) and gas chromatography/mass spectrometry (gc/ms). ten components were characterized representing 94.0% of the total components detected. the major constituents were: thymol (64.3%), p-cymene (10.3%), -terpinene (9.9%) and -caryophyllene (2.8%). the leaf oil demonstrated antibacterial activity against staphylococcus aureus, proteus vulgaris and aeromonas caviae as well as moderate fungicidal activity against aspergillus niger.