We compared in this study the in vitro potency of some antibiotics when used singly and in combination with another antibiotics and plant extracts against thirty-seven isolates of Staphylococcus aureusand fifty-five isolates of Escherichia coliusing disk diffusion method. Imepenem, Tobramycin, Nitrofurantoin, Ampicillin, Ciprofloxacin, Vancomycin, and Amikacin were randomly selected for this study. The isolates of E. coli and S. aureuswere previously identified from clinical specimens of human infections which included burn, wound, urine, and stool admitted to Internal Lab of Teaching Hospital. The samples were cultured on different culture media in order to test, isolate and identify of bacterial genera, according to the cultural characteristics, morphological features and biochemical reactions. Tremendous potencies were observed when the antibiotics used in combination compared with each antibiotic alone. The inhibition zone diameter increased significantly with combination between either two antibiotics or more in compare to monotherapy of antibiotics, and also there was recorded the significant different among antibiotics in alone status with combination status when saturated with plant extract against S. aureus only.