Andrographis paniculata, also called Chiretta or Kalmegh, is a medicinal plant which is traditionally used for the treatment of cold, fever and several infectious diseases. It is claimed that this plant contains immunological, antibacterial, antiinflammatory, antithrombotic and hepatoprotective properties. Biological synthesis of nanoparticles is one of the most eco-friendly methods as it replaces the use of toxic chemicals for the production of nanoparticles. In the present study, FeONPs were synthesized using A. Paniculata leaf extract, characterization of FeONPs was performed using UV–vis spectroscopy analysis which showed visible peak at 430 nm and Scanning Electron Microscopy (SEM) analysis revealed hexagonal structure and the size of nanoparticle to be 90 nm. FeONPs were more active considering antibacterial activity against Escherichia coli, Klebsiella pneumoniae and lesser antibacterial activity against Staphylococcus aureus. This activity may be due to the incorporate effect of the isolated arabinogalactan proteins and andrographolides. Thus, FeONPs produced using A. Paniculata could play a vital role in killing the bacterial pathogens and also in bioremediation.