In the inflammatory microenvironment, Lum/Ce6@PLGA nanoparticles can be oxidized by HClO, the MPO‐catalyzed product, generating light to stimulate Ce6 for the further production of 1O2, which can kill pathogens and induce the apoptosis of the excessive neutrophiles in the inflammatory lesion for alleviated tissue damage and improved animal survival in various peritonitis and pneumonia models. The gene discussed is MPO; the disease is peritonitis.