The field of nanotechnology is mushrooming and influencing human life very rapidly. Using plants for the synthesis of nanoparticles, is evolving as a new branch of nanotechnology. In plants, wide-ranging biomolecules act as reducing and capping agents, thereby increasing the reduction rate and stabilization of nanoparticles. This book focuses on green synthesis of silver nanoparticles (AgNPs) using methanolic extract of Lagenaria siceraria fruit mesocarp and its various fractions. The formation and characterization of AgNPs is established by UV-visible spectroscopy, fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). Afterwards its antimicrobial potential was studied keeping in view the folkloric medicinal uses of this plant. The results obtained showed that this plant is a potent candidate for drug discovery in future.