CAT and rheumatoid arthritis: In a second stage of internal biochemical regulation, owing to unique CAT‐ and SOD‐like activities of RuFOMs‐FA, the polarization of pro‐inflammatory M1 to anti‐inflammatory M2 macrophages in the RA physiological environment occurred by the steady‐state regulation of ROS levels in the inflamed joints and relieved synovium hypoxia simultaneously by generating massive O2.