Staphylococcus aureusandCandida albicanscells andAspergillus nigerspores were exposed to lethal doses ofThymus broussonettii, T. zygisandT. satureioidesessential oils and the numbers of surviving cells or spores were determined after various durations.T. broussonettiiexhibited the greatest potency, followed byT. zygisandT. satureioides.These results were discussed with respect to the chemical composition of the essential oils.C. albicanswas slightly more sensitive thanS. aureusto essential oil lethal effects, whileA. nigerwas relatively resistant, mainly toT. zygisandT. satureioides: about third to half the number of fungal spores were still alive after 4h exposure to 0.2% of essential oils.