A series of nitrodihydroxybenzenes and nitrocaffeic acids were prepared and their hydroxyl radical (OH degrees) and superoxide anion (O-2(-)) scavenging activities and xanthine oxidase inhibition activities were evaluated. 2-Nitrocaffeic acid is the more potent O-2(-) scavenger. 2-(and 5)-Nitrocaffeic acids are the more potent xanthine oxidase inhibitors.