Resveratrol, which is a polyphenol present in red wines and vegetables included in human diets, exerts many biological effects. The aim of the present study was to investigate its effect on some activities of polymorphonuclear leukocytes, particularly the generation of superoxide anion ((O2)(-)) in whole blood, hypochlorous acid (HOCl) and nitric oxide (NO) production by isolated cells, and chemotaxis. Resveratrol showed significant dose-dependent inhibitory effect on all these activities. In particular, it inhibited O2(-) generation in stimulated but not in resting neutrophils, decreased HOCl much more than O2(-) production indicating an effect on myeloperoxidase secretion since HOCl production is directly and proportionally dependent on O2(-) generation and reduced cell motility. The small dose of resveratrol (4.38 nM) used is attainable with a diet including red wine and vegetables confirming its protective role against some pathological processes such as inflammation, coronary heart disease, and cancer.