There are many methods to synthesize metal and metal oxide nanoparticles (NPs) using different reducing agents which are hazardous in nature. Although some researchers have used biobased materials for the synthesis of these NPs, further research is needed in this area. To explore the scope of bio-extract for the synthesis of transition metal NPs, the present paper synthesizes metal NPs replacing hazardous traditional reducing agents. This paper reports the synthesis zero-valent iron nanoparticles (ZVINs) by a green method and investigates the antibacterial activity of these nanoparticles through the extract of Thymus carmanicus. Green synthesis of Thymus carmanicu-Zero Valent Iron Nanoparticles (TC-ZVINs) was carried out in an alkaline environment. The TC-ZVINs were characterized by the use of imaging FESEM and spectroscopic (FTIR and XRD) methods. The TC-ZVINs obtained were a mixture of spherical and quasi-spherical shapes with diameters ranging between 40 and 80 nm. These methods demonstrated that some polyphenols are bound to the surfaces of the TC-ZVINs as a capping/stabilizing agent. Furthermore, The TC-ZVINs, TC extract and different percentages of them have the potential to terminate the pathogenicity of gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria. This property is slightly higher in the TC-ZVINs than in T. carmanicus extract. For both types of bacteria, the diameter of the inhibitory zone obtained from TC-ZVINs was about 10.8. تفاصيل المقالة