Ninety subjects (age 30~65) with Prehypertension or Hypertension stage 1 will be included and randomly allocated into 3 groups: Placebo, Djulis-Buckwheat and Buckwheat. The subjects will take sample (100 ml/day) for 8 weeks. Blood pressure will be measured on week 0, 1, 2, 4, 6 and 8. The blood biochemical parameters and gene expression analysis will be examined on week 2, 4, 6, 8 and 10 (the follow up).