The detergents of the next century will be routinely required to contain bleaching agents that are not only more active than those currently available but also environmentally safe and cost-effective. Hydrogen peroxide, the traditional bleaching agent(1), loses its activity as the washing temperature decreases. Peroxyacetic acid maintains acceptable bleaching activity down to 40-60 degrees C (ref. 2), but still lower temperatures are desirable. It if generally recognized that manganese and iron complexes are less environmentally damaging reagents than other transition-metal compounds, and such complexes have received considerable attention as bleaching catalysts(3-11). Here we show that manganese complexes derived from 1,4,7-trimethyl-1,4,7-triazacyclononane and related ligand systems act as highly effective catalysts for the bleaching of stains by hydrogen peroxide at low temperatures. These complexes also catalyse the epoxidation of alkenes and the oxidation of polyphenolic substrates by hydrogen peroxide. Our results demonstrate the considerable potential of these systems for clean and efficient low-temperature bleaching.