The antibacterial effect of the Eos extracted from Z. multiflora against the selected strains by the disk diffusion technique is presented on Table2. Standard antibiotics were used as positive controls which examined under similar conditions against all bacterial species. The results revealed that B. cereus with maximum inhibition zone was more susceptible when compared with ot her microorganisms(Po0.05). S.aureus and P.aeruginosa (P40.05) displayed more sensitivity to EOs than E.coli (Po0.05).Moreover, E.coli as gram-negative was the most resistant among tested strains (Po0.05).The antibacterial action of Z.multiflora Eos was found to Table1 Diameter of microbial inhibition zone(mm)of Z ataria multiflora essential oils determined by Agar well method. Be similar to the antibiotics. The antibacterial activity of oils against S. aureus and B. cereus strains was significantly comparable to the all antibiotics(Po0.05).Incase of P.aeruginosa ,Z.multiflora EOs exhibited comparable efficacy compared to Chloramphenicol (Po0.05).In addition, There are no significant differences between irradiated and non-irradiated samples in the antibacterial potency (P40.05).