In this study, the essential oil of Acroptilon Repens plant aerial parts, which was collected from Mahalat city, was extracted using water distillation method. In order to quantitatively and qualitatively identify the chemical compounds in the extracted essential oil, a gas chromatography device connected to a mass spectrometer (GC-MS) was used [1,2]. In the following, the capability of extracted essential oil in the preparation of iron oxide nanoparticles was evaluated [3]. The specifications and characteristics of the produced product were investigated by UV-Vis, FTIR, XRD, SEM, DLS and VSM methods. In this study, the efficiency of essential oil extraction was determined to be 1.1%. 21 chemical compounds in essential oil were identified from 22 components detected, separated and recorded by gas chromatograph (GC). Caryophyllene oxide (10.99%), beta-caryophyllene (14.14%), camphor (16.32%), O8-cineole (17.18%) and alpha-pinene (8.75%) were the main components of essential oil, which The total is 67.38% of the total essential oil. Based on the XRD results, as a result of the reaction of the extracted essential oil with a solution of Fe (III) salt, a mixture of iron oxides with the chemical structures of Fe3O4 and Fe2O3 has been prepared. The results of SEM, DLS and VSM analyzes respectively showed that the produced structure has an average particle size of 31.5 nm, a surface charge of +22.73 mV and a magnetic property of 1.5 electromagnetic units per gram. These results confirm the ability of bitter essential oil as an environmentally friendly reaction in the green preparation of iron oxide nanoparticle
