Allylpyrocatechol (APC) is responsible for the antiinflammatory activity exhibited by the methanolic extract of leaves ofPiper betle. As antiinflammatory compounds may display antioxidant properties andvice versa, we investigated the antioxidant effect of APC. APC effectively reduced phorbol-myristate-acetate-induced generation of reactive oxygen species and superoxide in murine peritoneal macrophages as well as inhibitedEscherichia-coli-induced phagocytic activity of macrophages. Furthermore, pBluescript SK+ plasmid DNA damage induced by addition of sodium ascorbate was attenuated by APC as it inhibited transformation of the supercoiled form to a relaxed form. In addition, APC increased the enzymatic (catalase) and nonenzymatic (GSH) antioxidant components of murine macrophages. Taken together, APC exhibited an antioxidant activity which was mediated both via decreased generation of free radicals along with increase in cellular antioxidants.