The efficacy and safety of powdered green tea containing long pepper extract for long term intake as a hypotensive agent was analyzed. The study, designed as a randomized double-blind placebo-controlled parallel-group study, was conducted in individuals with blood pressure in the high normal range and patients with first-degree hypertension. The subjects［60 subjects/group, 120 subjects in total（male/female＝93/27, age＝26-64 years old）］took either the test tea［powdered green tea containing 150 mg of long pepper extract（including 90μg of piperine）］or control tea（placebo; powdered green tea free of long pepper extract）once daily for 12 weeks. We observed systolic and diastolic blood pressures, side effect, adverse event, laboratory test data, body weight, and heart rate. The test tea group showed a significant reduction of both the systolic and diastolic blood pressures compared to the placebo group at each time-point of evaluation from Week 1 onward. The results from the stratified analysis by baseline blood pressure classification showed similar to all subjects. No adverse reactions were seen in any of the groups during the study period. These results confirmed that powdered green tea containing long pepper extract exerts a sufficient reduction of both the systolic and diastolic blood pressures, beginning from early as 1 week after the start of intake. Also no safety problems were observed. So, powdered green tea containing long pepper extract is expected to contribute greatly to primary prevention of hypertension.