In a randomized, parallel, double-blind study, lisinopril (n = 412; average dose 18.8 mg) reduced systolic and diastolic blood pressure (change = 20.2/13.8 mmHg; P < 0.01/P < 0.01) more than nifedipine (n = 416, average dose 37.4 mg; change = 13.3/11.2 mmHg) after 10-week treatment in patients, aged 40-70 years, with mild-to-moderate essential hypertension. Lisinopril was better tolerated than nifedipine. The withdrawals from treatment were fewer in the lisinopril-treated group (11 versus 46; P < 0.01). The frequency of adverse experiences reported after a general question of discomfort was significantly lower for lisinopril than for nifedipine (P < 0.01). When questioned on specific symptoms, frequency of coughing was higher with lisinopril (P < 0.01), while flushing, edema, palpitations, dizziness, tiredness and rash were reported more frequently (P < 0.01, for all) in the nifedipine-treated group. Quality of life was assessed by both patients and spouses. No significant changes in wellbeing were observed for either drug, except for the highest dose level of nifedipine which caused a deterioration.