Conventional cancer treatments often have significant side effects and limitations. Nanoparticles (NPs) offer promising alternatives, providing enhanced specificity, efficiency, multifunctionality, and personalized therapy. This chapter discusses the benefits of NPs in cancer treatment, emphasizing their ability to target specific cells or tissues via ligands or antibodies, thereby reducing off-target effects and systemic toxicity. NPs can effectively penetrate tumor tissues, carry multiple therapeutic agents for synergistic effects, and integrate imaging agents and biomarkers for real-time monitoring, significantly improving patient outcomes. This chapter also introduces the major classifications of NPs (organic and inorganic) and highlights the importance of environmentally friendly synthesis methods. Traditional methods are costly and environmentally hazardous, whereas green synthesis using plant extracts is more economical, safer, and time efficient. Additionally, it also covers the characterization of NPs, examining their physical and magnetic properties via various techniques. These detailed analyses highlight the potential applications and benefits of NPs in cancer treatment, making them safer and more effective alternatives to traditional therapies.