he chemical composition of the essential oils obtained by hydrodistillation from fully-formed, dried oregano leaves (Origanum vulgareOriganum vulgare) and lavender leaves and flowers (Lavandula officinalis) were analyzed by GC/MS. The effectiveness of oregano (OEO) and lavender (LEO) essential oils and a mixture LEO:OEO (50:50) in inhibiting Escherichia coli and Staphylococcus aureus growth were determined. Both essential oils inhibited the growth of the microorganisms tested, being more sensitive to gram-positive bacteria