RATIONALE: Experimental studies have shown a potential blood pressure (BP) lowering effect of red wine polyphenols, whereas the effects of ethanol and polyphenols on BP in humans are not yet clear. OBJECTIVE: The aim of the present work was to evaluate the effects of red wine fractions (alcoholic and nonalcoholic) on BP and plasma nitric oxide (NO) in subjects at high cardiovascular risk. METHODS AND RESULTS: Sixty-seven men at high cardiovascular risk were studied. After a 2-week run-in period, subjects were randomized into 3 treatment periods in a crossover clinical trial, with a common background diet plus red wine (30g alcohol/day), the equivalent amount of dealcoholized red wine, or gin (30g alcohol/day), lasting 4 weeks each intervention. At baseline and after each intervention, anthropometrical parameters, BP and plasma NO were measured. Systolic and diastolic BP decreased significantly after the dealcoholized red wine intervention and these changes correlated with increases in plasma NO. CONCLUSIONS: Dealcoholized red wine decreases systolic and diastolic BP. Our results point out through an NO-mediated mechanism. The daily consumption of dealcoholized red wine could be useful for the prevention of low to moderate hypertension. Trial registered at controlled-trials.com: ISRCTN88720134.