Species such as superoxide radical (O2−), hydrogen peroxide (H2O2), hydroxyl radical (·OH), and hypochlorous acid (HOC1) can be formed in vivo, e.g., by activated phagocytic cells. Generation of·OH from H2O2in vivo usually involves iron‐dependent reactions. Good evidence exists for increased generation of oxidants in vivo in patients with active rheumatoid disease, but the contribution of these oxidants to the disease process is still uncertain. The likelihood that anti‐inflammatory drugs used in the treatment of arthritis could act by scavenging oxidants or preventing their formation is discussed.— Halliwell, B.; Hoult, J. R.; Blake, D. R. Oxidants, inflammation, and anti‐inflammatory drugs.FASEB J.2: 2867‐2873; 1988.