Background: The aim of this study is to evaluate the efficacy of resveratrol (trans-3, 5, 4’-trihydroxystilbene, a polyphenol present in grapes) in comparison with the placebo on blood pressure in participants with pre- and stage-1 hypertension. Design and Methods:In a randomized, double blind, placebo-controlled study, 50 participants with pre-hypertension (diastolic blood pressure and systolic blood pressure, 80- 89 mmHg and 120-139 mmHg, respectively) and 50 participants with stage 1 hypertension (diastolic and systolic, 90-99 mmHg and 140-159 mmHg, respectively) will be assigned to sequence A or B to receive resveratrol (99% pure from BIOTIVIA LONGEVITY BIOCEUTICALS LLC Company, USA, in 500 mg capsules, twice daily for 4 weeks, orally) or placebo (500 mg neutral micro cellulose capsules, twice daily for 4 weeks) in a 2×2 cross-over design (4 weeks treatment-4 weeks washout-4 weeks treatment). The participants’ blood pressure will be recorded (the average of two times within 15 minute interval) every week during the study. The participants in the pre-hypertensive group will not have any medication, while those in the stage 1 hypertensive group will continue to receive their routine medications during the study. Blood samples will be taken from all groups and examined for various biochemical parameters.