This review article summarizes the use of silver as an antimicrobial, its mechanism of action, general introduction of silver nanoparticles, synthesis, toxicity, its medical application. Silver is a health additive added in customary traditional Chinese and Ayurvedic medicine. Its action is antibiotic and it is non selective toxic biocide. Silver has been effective against all organism tested and used to treat numerous infection and non infectious condition. Silver is incorporated in wound dressing and used as antibacterial coating in medical devices. Silver ion is bioactive and mainly responsible for bactericidal action. This review also covers the major use of silver in form silver nanoparticle as it has broad spectrum bactericidal and fungicidal activity. Bactericidal nanoparticles are gaining importance because the size of the nanoparticles is similar to biological molecules and are used in in vitro and in vivo biomedical studies. Metallic nanoparticles are better nanoparticles with best antibacterial properties as these increase chemical activities due to crystallography surface structure. Nanoparticle of silver brings the significant improvement in the antibacterial activity.