Green synthesis of metal nanoparticles (NPs) from plant extracts has attracted significant interest in modern medicine. Therefore, this study prepared an aqueous extract of Sophora flavescens roots, which are used in folk medicine to treat several diseases, including bacterial infections. In addition, silver NPs (AgNPs) were synthesized from root extract using the green synthesis method. The NPs were diagnosed using modern methods. Additionally, the antibacterial activity of the root aqueous extract and AgNPs aqueous preparation (at concentrations of 7% and 9%, respectively) was examined against selected isolates of multidrug-resistant Pseudomonas aeruginosa and Staphylococcus aureus. The results indicated that both the plant extract and NP preparations inhibited pathogenic bacterial isolates.