As a result of the emergence of new virus strains and the emergence of microorganisms resistant to various antibiotic synthetics, virus infections pose significant global health challenges, so the need for new therapeutic drugs rises as new viral and bacterial infectious diseases emerge. This study aimed to synthesize silver nanoparticles from Nigella arvensis aqueous extract and investigate their possible antiviral and antibacterial properties. X-ray diffraction, transmission electron microscopy, and UV-Visible spectroscopy were used to validate the synthesis of Ag-NPs. The findings are based on detecting Ag-NPs production through the shift from yellow color to dark brown color. TEM examination of Ag-NPs revealed spherical nanoparticles with mean sizes ranging from 2 to 9 nm and an average particle diameter of 2.5 nm. A UV-Visible spectrophotometric investigation revealed an absorption peak at λ max of 424 nm. However, Ag-NPs exhibit antimicrobial action against the four studied bacteria, with the inhibition zones for Bacillus subtilis ranging from 6 to 25 mm, Staphylococcus aureus from 8 to 25 mm, and Escherichia coli from 10 to 19 mm, whereas Pseudomonas aeruginosa has shown resistance to the AgNPs solution. The MBC varied from 22.3 to 36.8 μg/mL, whereas the MIC for the produced silver nanoparticles against the chosen bacterial strains ranged from 5.7 to 10.2 μg/mL. According to the maximum non-toxic concentration (MNTC) of Ag-NPs, 10.56 µg/mL, the greenly generated Ag-NPs of Nigella arvensis showed outstanding antiviral efficacy against HSV-1, HAV, and adenovirus by inhibiting replication by 53.6, 86, and 17.3 correspondingly. Finally, The novelty in this study is the application of silver nanoparticles as an antiviral against HSV-1, HAV, and adenovirus because of the high mutation of viruses.