The generation of reactive oxygen species (ROS) is an important mechanism of nanomaterial toxicity. We found that Prussian blue nanoparticles (PBNPs) can effectively scavenge ROS via multienzyme-like activity including peroxidase (POD),. catalase (CAT), and superoxide dismutase (SOD) activity. Instead of producing hydroxyl radicals (center dot OH) through the Fenton reaction, PBNPs were shown to be POD mimetics that can inhibit center dot OH generation. We theorized for the first time that the multienzyme-like activities :of PBNPs were likely caused by the abundant redox potentials of their different forms, making them efficient electron transporters. To study the ROS scavenging ability of PBNPs, a series of in vitro ROS-generating models was established using, chemicals, UV irradiation, oxidized low-density lipoprotein, high glucose contents, and,oxygen glucose deprivation and reperfusion. To demonstrate the ROS scavenging ability of PBNPs, an in vivo inflammation model was established using lipoproteins in Institute for Cancer Research (ICR) mite. The results indicated that PBNPs hold great potential for inhibiting or relieving injury induced by ROS in these pathological processes. electrochemistry,