Abstract: The antibacterial activities of hot water, methanol and ethanol extracts of 5 plant extracts utilized in Palestine in popular medicine were studied. The dried extracts of Syzyium aromaticum (Myrtaceae) (seed), Cinnamomum cassia (Lauraceae) (cassia bark, Chinese cinnamon) (bark), Salvia officinalis (Lamiaceaea) (leaf), Thymus vulgaris (Lamiaceaea) (leaf) and Rosmarinus officinalis (Labiatae) (leaf) were tested in vitro against 4 bacterial species by disk diffusion and micro-dilution. The patterns of inhibition varied with the plant extract, the solvent used for extraction, and the organism tested. Methicillin-resistant Staphylococcus aureus (MRSA) and Bacillus subtilis ATCC 6633 were the most inhibited microorganisms. S. aromaticum extract was the most active against multidrug resistant Pseudomonas aeruginosa and enterohemorrhagic Escherichia coli O157 EHEC. The combinations of ethanolic extracts of S. officinalis with R. officinalis and of R. officinalis with T. vulgaris on bacterial species tested exhibited a higher effect than that of any individual extract. Results of this kind herald the interesting promise of designing a potentially active antibacterial synergized agent of plant origin.