A randomized controlled open trial studied the effect of vitamin E supplementation (300 mg/day) on clinic and 24-h ambulatory blood pressure (BP) in 142 treated hypertensive patients. After 12 weeks, clinic BP decreased whether or not patients were randomized to vitamin E. Ambulatory BP showed no change in systolic BP and a small decrease in diastolic BP (-1.6 mm Hg, 95% confidence intervals from -2.8 to -0.4 mm Hg), approaching statistical significance in comparison to the control group (P = .06). Vitamin E supplementation thus seems to have no clinically relevant effect on BP in hypertensive patients already under controlled treatment.