Perindopril 4 mg once daily was given to 40 hypertensives for 4 weeks. The results showed that systolic and diastolic blood presure were decreased by 3.2 kPa (22.2 +/- 2.21-19.0 +/- 1.92 kPa) and 1.87 kPa (13.4 +/- 1.21-11.5 +/- 1.27 kPa), respectively. The total effective rate was 80%. Serum Angiotensin-I-converting enzyme activity in 30 patients was significantly decreased from 58.5 +/- 29.5 U to 18.2 +/- 16.2 U (P < 0.01). The urine level of N-acetyl-beta-D-glucosaminidase (NAG) in 27 patients significantly decreased from a prior level of 13.66 +/- 7.81 U.gCr-1 to 10.12 +/- 5.57 U.gCr-1 (P < 0.01). The side effects of perindopril were cough (7.5%), constipation (10%), dizziness (7.5%), flatulence (7.5%) and diarrhea (5%). We conclude that perindopril is a potent antihypertensive drug with significant prevention on hypertension-induced early renal damage.