For effective and safe IBD treatment, herein a smart nanotherapy (i.e. oxidation‐responsive nanoparticles containing a proresolving annexin A1‐mimetic peptide Ac2‐26, defined as AON) is developed, which can release packaged Ac2‐26, in response to highly expressed reactive oxygen species (ROS) at diseased sites. The gene discussed is ANXA1; the disease is inflammatory bowel disease.