In this investigation, six medicinal plants; Argemone mexicana, Jatropha variegata, Lawsonia inermis, Salvadora persica, Withania somnifera and Ziziphus spina-christi were tested for their antibacterial activity against seven strains of gram positive bacteria and two gram negative bacteria. Generally, gram positive bacteria were mere sensitive toward .he different concentrations of plant extracts than gram negative bacteria. In addition, plan methanol extracts possessed higher inhibitory effect than water extracts. Withania somnifera methanol extract exhibited the highest inhibitory effect against the tested bacteria while, Argemone mexicana water extract showed the lowest inhibitor effect. All tested extracts showed significant effect against the tested bacteria. The maximum inhibition zone was recorded against Staphylococcus aureus while, the minimum inhibition zone was recorded against Streptomyces sp.