This study was carried out to investigate the potential of using essential oil extract of Lemongrass (Cymbopogon citratus) as natural antibacterial agent at three different concentrations (100, 200 and 500 X10³ppm) against 60 human isolates from diarrheal and septicemic cases in addition to 7 ATCC (American Type of Culture Collection) strains belonging to 3 different species of Gram negative bacteria including Salmonella spp, Shigella spp and Campylobacter spp and one Gram positive bacteria which is Staph. aureus. The screening was performed by standard disc diffusion method. Essential oil extract of lemongrass exhibited maximum activity against C. jejuni with 30.62 mm, Staph. aureus with 11.91 mm, Shigella spp with 11.73 mm and Salmonella spp with 9.41 mm mean diameter of zone of inhibition at the lowest used concentration, 100x10³ ppm of the essential oil. Accordingly, lemongrass essential oil extract was found to be effectively inhibiting both gram-positive and gram-negative bacteria and can be a good source of antibacterial agents for possible infections in poultry products.