Sodium restriction by 50 to 100 mmol/day in populations with intakes averaging 150 to 180 mmol/day would likely lead to a reduction of population mean blood pressures, and less of a tendency for blood pressures to rise with age. Fewer people would require antihypertensive drug therapy, and those who did would require less drugs. The extent of any blood pressure fall would be greatest in the elderly or those with established hypertension. A corresponding reduction in stroke incidence might be anticipated, with less certain effects on coronary deaths and diseases. Other factors, such as weight control, alcohol moderation and increased physical activity, may be of greater importance in preventing hypertension in many populations, while cessation of smoking, control of obesity, increased physical fitness and reduction in dietary saturated fat consumption should probably receive the highest priority in terms of overall reduction in the risk of atheromatous cardiovascular disease. In countries such as Japan, which has a relatively high incidence of stroke and a low incidence of coronary disease, a high sodium intake assumes relatively greater importance, in conjunction with obesity and alcohol, as a risk factor for cerebrovascular disease.