This study explored the antibacterial properties of silver nanoparticles both in vitro and in vivo. In vitro assays found that silver nanoparticles were effective against both gram-positive and gram-negative bacteria. Gram-positive bacteria were more sensitive, with Staphylococcus aureus exhibiting the largest zone of inhibition. The minimum inhibitory concentration needed to show effects was lower for gram-positive compared to gram-negative bacteria. In vivo assays in mice found that silver nanoparticles were effective in reducing symptoms and improving survivability when administered after bacterial injection.