The kinetics of the oxidation of ruthenium(III)- and osimum(VIII)-catalysed oxidation of paracetamol by diperiodatoargentate(III) (DPA) in aqueous alkaline medium at a constant ionic strength of 0.10 mol dm(-3) was studied spectrophotometrically. The reaction between DPA and paracetamol in alkaline medium exhibits 2:1 stoichiometry in both catalysed reactions (DPA:PAM). The main products were identified by spot test, IR, NMR and GC-MS. Probable mechanisms are proposed and discussed. The activation parameters with respect to the slow step of the mechanism are computed and discussed and thermodynamic quantities are also calculated. It has been observed that the catalytic efficiency for the present reaction is in the order of Os(VIII) > Ru(III). The active species of catalyst and oxidant have been identified. (c) 2006 Elsevier B.V. All rights reserved.