1. In 20 of 20 patients (100%) with borderline hypertension Visken normalized the labile blood pressure. The high renin values after stimulation due to orthostasis and saluresis decreased significantly (p less than 0,01). 2. In 3 of 12 patients (25%) with hyporeninemic essential hypertension Visken alone normalized the blood pressure. The low renin values increased to the normal range. 3. In 4 of 18 patients (22%) with normoreninemic essential hypertension Visken normalized the blood pressure. The normal renin values showed a decreasing tendency within the normal range. 4. In 4 of 10 patients (40%) with hyperreninemic essential hypertension Visken normalized the high blood pressure. In 3 of these patients renin decreased distinctly. 5. In 4 of 20 patients (20%) with renal hypertension a therapy with Visken alone normalized the blood pressure. In 3 patients the high renin values decreased to the normal range. 6. In the most other patients of the groups II to V the additional therapy with diuretics and reserpine normalized the blood pressure. In these cases the renin values showed different reactions corresponding to the different effects of betablocking agents, saluretics or reserpine on the plasma renin activity [7]. 7. It is interesting, that Visken not only suppresses high renin values (borderline hypertension [6], hyperreninemic essential hypertension), but also increases low renin values to the normal range in patients with hyporeninemic essential hypertension. Because in essential hypertension the high blood pressure per se may be responsible for the renin suppression [3,4], this increase of renin activity is possibly the consequence of blood pressure reduction, while the decrease of renin activity after Visken may be the cause of blood pressure reduction.