BACKGROUND: The goal of antihypertensive therapy will be to extended the life expectancy of hypertensive patients to that of subjects without high blood pressure. Hypertension treatment in the 1990s will focus on the mechanisms by which blood pressure is lowered by various antihypertensive agents, as will as individualization of drug therapy. In recognition of their lack of adverse lipid effects and their tolerability, first line therapy with alpha blocker, angiotensin converting enzyme inhibitors and calcium antagonists will become increasingly commom. We studied a new dihydropyridine calcium antagonist barnidipine to evaluate the efficacy and safety in patients with essential hypertension. METHODS: The rabit aortic rings were cut and mounted on the force transducer to record an isometric tension on polygraph. To elucidate the mechanism of saponin effect on vascular smooth muscle, the contractility of the vascular smooth muscle were measured under vatying experimental condition. RESULTS: 1) The baseline sitting systolic and diastolic blood pressure after 4 weeks washout period were 154.+/-15.9mmHg and 1.0+/-8.2mmHg. At the end of 8 weeks of therapy sitting systolic and diastolic blood pressure were 126+/-9.5mmHg and 84.5+/-4.6mmHg which declined statistically significant(p<0.05). 2) The pulse rates did not change significantly during treatment period(70.0+/-6.6 beats / min at baseline, 70.9+/-7.2 beats / min at 2 weeks, 71.2+/-5.0 beats / min at 4 weeks, 72.8+/-8.5 beats / min at 6 weeks, and 71.9+/-6.8 beats / min). 3) The adverse reactions due to branidipine were reported in 2 patients(6.5%) with headache, 2 patients(6.5%) with facial flushing, 1 patient(3.4%) with dizziness and 1 patients(3.4%) with nausea and vomiting). 4) The abnormal laboratory findings due to barnidipine were reported in 1 patient with increased total bilirubin and GPT, 1 patient with increased transaminase and 1 patient with CK but another findings were normal. CONCLUSION: These results indicate that barnidipine is effective and safe antihypertensive agent in the treatment of essential hypertension.