Abstract: Disk diffusion and micro-dilution techniques were used to determine the antibacterial activity of water, ethanolic and methanolic extracts of Rhus coriaria ripe berries against five clinical bacterial strains (Methicillin-resistant Staphylococcus aureus (MRSA), multi-drug resistant Pseudomonas aeruginosa, enterohemorrhagic Escherichia coli O157 (EHEC), Proteus vulgaris and Klebsiella pneumoniae). Bacillus subtilis ATCC6633 was used as a reference strain. The zone of inhibition varies depending on bacterial species and type of extract. The average diameter of inhibition zones ranges from 0 to 19 mm, 15 to 25 mm and 15 to 22 mm
for water, ethanolic and methanolic extract, respectively. The MIC value of ethanolic extract was 1.25 mg/ml against MRSA, EHEC, P. aeruginosa and Proteus vulgaris, while 0.156 mg/ml against B. subtilis. In general these results showed that the antibacterial activity of R. coriaria ripe berries extracts was more effective against Gram-positive bacteria than Gram-negative.