The inhibitory effects of essential oils as well as chloroformic extracts of Thymus vulgaris, Thymus serpyllum, Salvia officinalis and Pimpinella anisum grown in Ash-shoubak region-south of Jordan and their possible individual phytochemical constituents was screened against pathogenic clinical and standard strains of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The bioassay employed was the agar well diffusion method. The essential oils and chloroformic extracts of T. vulgaris and T. serpyllum were the most effective against the tested strains of bacteria. Clinical and standard strains of S .aureus and P. aeruginosa were uninhibited by S. officinalis essential oils. P. aeruginosa tested strains were also resistant to P. anisum essential oils. For almost all bacterial strains, the highest antibacterial effect of oils was obtained with the highest tested dose (15 μl). Chlorformic extracts of S. officinalis showed small activity against standard and clinical E. coli strains and were not effective to inhibit strains of P. aeruginosa and S. aureus. Chloroformic extracts obtained from P. anisum and applied at 300 μg/cm(2) slightly inhibited E. coli, but moderately inhibited S. aureus. It is shown from the results that the antibacterial effects of the individual components varied depending upon their chemical structure, functional groups and configuration as well as doses used. This study showed the beneficial effects of the essential oils of T. serpyllum and T. vulgaris grown in Ash-shoubak in inhibiting the growth of microbes and the implications this could have in pharmacy and food technology.