Silver nanoparticles (Ag-NPs) reflects high potential as an effective antimicrobial, cancer therapy with minimal side effects. Ag-NPs preparation techniques is designed as an ecofriendly manner. Using the flower extract of Calotropis gigantea plant, a powerful medicinal plant used to cure a variety of ailments, we biologically synthesized Ag-NPs using methanol in this study. The phytochemicals found in medicinal plants, such as polyphenols, flavonoids, and tannins, serve as reducing and stabilizing agents. As a result, they can be used in biological synthesis processes. The work suggests a novel strategy that biosynthesized Ag-NPs. Utilising a variety of techniques, the biosynthesized Ag-NPs were characterized, and the MCF-7 cell line was used to test their cytotoxicity. Surface plasmon resonance bands for Ag-NPs was discovered using ultraviolet-visible spectroscopy at 425 nm. Antibacterial activity of Silver nanoparticles of Calotropis gigantea flower extract was carried out against bacterial pathogens like Escherichia coli and Salmonella typhi by disc diffusion method. Maximum zone of inhibition were noticed in the Salmonella typhi followed by Escherichia coli. All the values showed p<0.001 level of significance