Aim: Present work was undertaken to fabricate iron oxide nanoparticles (IONPs) using a green approach for increased therapeutic efficacy. Materials & methods: Two types of IONPs were synthesized, one without any coating (IONPUC) and other coated with Phyllanthus emblica (Amla) fruit extract (IONPA). Both the IONPs were characterized using different techniques and therapeutic efficacy was evaluated in A549 human lung cancer cell line. Results: IONPA were smaller in size with better dispersibility compared with IONPUC. They induced increased reactive oxygen species production, higher DNA damage and apoptosis, which resulted in increased toxicity to cancer cells in comparison to IONPUC. Conclusion: Higher uptake of IONPA and active components coating the surface, may be responsible for the increased therapeutic efficacy in cancer cells.