The removal of hexanal by a combination of a non-thermal plasma and catalyst was studied. There was a synergism between the plasma and gamma-Al2O3 that gave a hexanal removal efficiency of 87.1% at 80 degrees C and 2.8 W discharge power. The removal efficiency was improved to 96.5% when the gamma-Al2O3 was loaded with 7.5% MnOx, and a comparable efficiency was also obtained with a Pt/gamma-Al2O3 catalyst. The 7.5%MnOx/gamma-Al2O3 catalyst was stable over 50 h use during which the removal efficiency did not decline.