This research aims to develop a novel approach, employing cold plasma technology for preparing nanoparticles of silver oxide by Anethum graveolens (dill) leaf extract as a natural reducing agent. This investigation evaluated the properties of antibacterial and antibiofilm-prepared nanoparticles. Initially, dill leaf extract was prepared to stabilize and reduce the size of silver oxide nanoparticles. Improved synthesis and optimal conditions for nanoparticle formation were achieved through the application of cold plasma technology. The results obtained showed that the prepared silver oxide nanoparticles have strong antibacterial properties and that they have antibacterial activity against a different group of bacteria that cause diseases such as Klebsiella pneumoniae (K. pneumoniae), Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The results also showed the effectiveness of nanoparticles in preventing the formation of bacterial biofilms, as the highest rate of inhibition was for gram-positive bacteria S. aureus. This study demonstrated the effectiveness of plant extracts and cold plasma technology when combined in producing nanoparticles with improved properties, which may push toward the employment of these materials in developing innovative and sustainable solutions in various scientific and applied fields.