Choices among medical treatments when the results of such treatment are well known and beyond doubt are few, for instance, penicillin for pneumococcal disease or standard drugs for active tuberculosis. It is quite another matter when outcome is uncertain. The evidence that morbidity or mortality from coronary artery disease among severe hypertensives has been significantly reduced by antihypertensive treatment is at best debatable despite the claims of the Hypertension Detection and Follow-Up Program study. The data available before publication of the Medical Research Council trial of treatment in mild hypertension did not help to reconcile opposing views about whether patients with arterial pressures in excess of 140/90 really benefited from treatment. Coronary artery disease is the leading cause of death in the United Kingdom, responsible for one-third of all deaths among men and one-quarter among women. The report on the prevention of coronary disease in the United Kingdom comes from the Working Party of the British Cardiac Society.