BACKGROUND Epidemiological data suggest that modest red wine consumption may reduce cardiovascular disease risk. Red wine polyphenols improved human endothelial vascular function and reduced blood pressure (BP) in animal studies, but the results of human intervention studies investigating the effect of red wine polyphenols on BP are inconsistent. The objective was to investigate whether polyphenols extracted from red wine reduce peripheral and central BP in subjects with high-normal BP or grade 1 hypertens METHODS In a double-blind, placebo-controlled three-period crossover trial, we assigned 61 subjects (mean age 61.4 +/- 8.4 years) with office systolic BP 135 +/- 9 mm Hg and diastolic BP 82 +/- 8 mm Hg to dairy drinks containing either placebo, 280 mg red wine polyphenols, or 560 mg red wine polyphenols. After each 4-week intervention period, office and 24-h ambulatory BP measurements, and central hemodynamic measurements derived from continuous finger BP recordings were assessed. RESULTS Polyphenol treatment did not significantly affect 24-h BP: systolic/diastolic BP was 143 +/- 2/84 +/- 1 mm Hg after placebo, 143 +/- 2/84 +/- 1 mm Hg after 280 mg/day of red wine polyphenols, and 142 +/- 2/83 +/- 1 mm Hg after 560 mg/day. Neither dose of polyphenol treatment changed office or central BP, aortic augmentation index (AIx) or pulse wave reflection index. CONCLUSIONS Intake of red wine polyphenols in two different dosages for 4 weeks did not decrease peripheral or central BP in subjects with a high normal or grade 1 hypertension. Our findings do not support the hypothesis that polyphenols account for the suggested cardiovascular benefits of red wine consumption by lowering BP.