In this paper, Lanthanum and Cerium oxide (La2O3 and CeO2) nanoparticles were synthesized using Ficus Religiosa leaves extract. The synthesized NPs were characterized using UV-visible for obtaining optical spectra, and FTIR for showing respective band stretch and structure. The purity and structural phase were determined by powder X-ray Diffraction (XRD), and the observed average nanocrystallite size is 3-20 nm. The surface morphology and shape of materials were analyzed by Scanning electron microscope (SEM), Transmission electron microscope (TEM) and High-Resolution Transmission electron microscope (HR-TEM). The observed shapes are rod-shaped, round, cubic and irregular. The observed size of nanoparticles is 5-50 nm. BET analysis shows an increment from a value of 7.243 m2 g-1 to 45.144 m2 g-1 and peak pore volume increases from 0.074278 cm3 g-1 to 0.1904 cm3 g-1. The antibacterial activity was performed against various Gram-positive and Gram-negative bacteria. Further, nanoparticles were tested for haemolytic studies to observe the percentage of haemolysis on red blood cells.