We have studied 250 patients with mild to moderate essential hypertension (diastolic blood pressure 95-114 mmHg) and dyslipidaemia (high-density lipoprotein cholesterol (HDL-C) below 1.03 mmol.l-1, total cholesterol 5.17-9.05 mmol.l-1, and triglycerides 2.26-5.64 mmol.l-1) in a controlled double-blind, multicentre, parallel group trial. The patients took a fat-modified diet. After a 4-week placebo period, patients who continued to fulfil the selection criteria were randomly allocated to treatment with either carvedilol (a vasodilating beta-blocker) 25-50 mg o.d. (n = 116) or captopril (an ACE inhibitor) 25-50 mg o.d. (n = 117) for 6 months. In both groups there were favourable effects on the serum lipids. The relative changes (medians) in the carvedilol and captopril group were respectively: increase in HDL-C by 11% and 8%, decrease in total cholesterol by 11% and 10%, in low-density lipoprotein cholesterol by 16% and 12%, and in triglycerides by 13% and 14%. Equivalence of the two treatments was confirmed for the target variable change in HDL-C at a significance level of 5%. Reductions in supine systolic/diastolic blood pressures were comparable in the two groups (carvedilol: 23/19 mmHg, captopril: 20/18 mmHg). The improvement in lipid metabolism in patients treated with carvedilol is probably due to its alpha 1-blocking properties.