Gallic acid capped gold nanoparticles having narrow size-distribution obtained at ambient temperature (25 °C). Gold nanoparticles were stable at different concertation of glucose and bovine serum albumin (BSA). Dose dependent cytotoxicity of gold nanoparticles have examined in mouse embryonic fibroblast (MEF) cells. The results showed low viability with high dose of gold nanoparticles (200–400 ppm). Gold nanoparticles are safe for both gram positive and gram negative bacterial cells.