Nanozymes, in nature, are artificial enzymes. Innovated by Ronald Breslow to mimic enzymes. Nanozymes have widespread applications including targeted cancer therapy, diagnostic medicine and bio-sensing even environmental toxicology. However, these applications are a novel research field in biomedicine, but are growing fast. Enzyme-based applications such as immune-absorbent assay (ELIZA) are expensive because of the complexity of producing enzymes and antibodies. Not only, some nanoparticles can mimic these enzymes such as superoxides, but also they can manipulate biological pathways directly like autophagy. These abilities make them a suitable alternative for both therapy and diagnosis. In this review, we opted on metal nanoparticles and application of this cutting edged technology into modern medicine.