The introduction of the western diet and lifestyle to Japan has been associated with changes in body build, lipid levels, and disease pattern. An increased incidence of coronary heart disease parallels increased fat intake. Thiazide diuretics and beta blockers may have adverse effects on blood lipids in man leading to an increase in the risk of coronary heart disease; therefore, for many patients these drugs may not offer the optimum treatment strategy. Hence, prazosin, a drug that effectively lowers blood pressure without adversely affecting lipid metabolism, has been evaluated in nine studies within Japan. Prazosin showed adequate antihypertensive effects even at doses as low as 1 to 3 mg per day. Sustained constant blood pressure reductions were achieved with maintenance doses of 3 to 6 mg per day without significant side effects. Even when given in low doses, prazosin increased high-density lipoprotein cholesterol while inhibiting elevations of total cholesterol and decreasing triglycerides. In view of these findings, prazosin as a single agent can be considered for monotherapy of hypertension.