Synthetic antibiotics have been successfully utilized for decades against pathogenic bacteria to control infectious diseases. However, the continuous and overuse has resulted in multidrug resistant (MDR) bacterial species. Further, the negative side effects caused by commercial antibiotics also hindered their usage. The phytochemicals produced by plants in response to adverse biotic and abiotic conditions possess significant pharmacological properties and can be an effective alternative to synthetic antibiotics. The phytochemicals of Ageratinaadenophora, served the role of reducing and stabilizing agent. Ageratinaadenophora mediated silver nanoparticles (Aa-AgNPs) were characterized using advanced spectroscopic instrumentation. The qualitative analysis by GC-MS showed Methyl ionone, 2(3H)-Naphthalenone, 4, 4a, 5, 6, 7, 8- hexahydro-4a,7,7-trimethyl-(R), Isolongifolone as the major compounds. The quantitative estimation showed leaves were rich in total phenol, flavonoids, alkaloids and tannins. The Aa-AgNPs were effective in inhibiting bacterial pathogens. Further, A.adenophora mediated nanoparticles possessed strong antioxidant activity.