Oxidation of thioglycolic, thiolactic and thiomalic acids by morpholinium fluorochromate (MFC) in dimethylsulphoxide (DMSO) leads to the formation of disulphide dimers. The reaction is first order in MFC. Michaelis-Menten type of kinetics is observed with respect to the thioacids. Reaction failed to induce the polymerisation of acrylonitrile. The reaction is catalysed by hydrogen ions. The hydrogen ion dependence has the form kobs = a + b [H+]. The oxidation of thiolactic acid has been studied in nineteen different organic solvents. The solvent effect has been analysed by using Kamlet’s and Swain’s multiparametric equations. A mechanism involving the formation of a thioester and its decomposition in slow step has been proposed.