['Bacterial infections continue to pose a threat to health in many institutional and communal settings, and epidemics are frequent. Current control measures are clearly inadequate; thus, there is a need for a simple, effective, and safe way to decontaminate surfaces.', 'We evaluated the efficacy of a portable ozone-generating machine, equipped with a catalytic converter and an accessory humidifier, to inactivate 15 different species of medically important bacteria.', 'An ozone dosage of 25 ppm for 20 minutes, with a short burst of humidity in excess of 90% relative humidity, was able to inactivate more than 3 log(10) colony-forming units of most of the bacteria, including Acinetobacter baumannii, Clostridium difficile, and methicillin-resistant Staphylococcus aureus, in both in a laboratory test system and simulated field conditions. In many cases, complete eradication was achieved. Dried and wet samples were equally vulnerable to the ozone. Inactivation of bacterial samples dried onto soft surfaces (eg, fabric, cotton, filter paper) were comparable with that observed for samples on plastic.'] Is ozone gas an effective and practical antibacterial agent?