European and American recommendations for coronary heart disease prevention put patients with clinically manifest coronary heart disease, or other major atherosclerotic disease, as the top priority for prevention. Coronary patients should have professional support to stop smoking, eat a healthier diet (reduce the dietary intake of fat to 30% or less of total energy; saturated fat to no more than one third of total fat intake, cholesterol to less than 300 mg per day; increase monounsaturated and polyunsaturated fat from both vegetables and marine sources; increase fresh fruit and vegetables) achieve optimal weight, and become physically fitter through regular aerobic exercise. The intensity of lifestyle intervention and the level of professional support required to achieve change should be determined by the absolute risk of a further major ischaemic event, based on an assessment of all risk factors, and this should also influence the threshold for drug therapy in relation to blood pressure, lipoproteins and glucose, rather than just the individual levels of these risk factors. In addition to lifestyle changes (reducing weight and restricting salt and alcohol as appropriate) blood pressure in coronary patients should be lowered if necessary with drug therapy. For these patients blood pressure should be consistently less than 140/90 mmHg. Lifestyle changes will reduce total cholesterol (and in particular LDL cholesterol) increase HDL cholesterol and lower triglycerides. Drug therapy may also be required and in coronary patients total cholesterol should be kept consistently below 4.8 mmol.l-1, and this threshold may be further reduced with the publication of new trial results. In insulin-dependent diabetes, rigorous metabolic control reduces the risk of microvascular complications and therefore for coronary patients with insulin-dependent or non-insulin dependent diabetes mellitus this is a desirable objective. As diabetics with coronary disease are at substantially higher risk of coronary morbidity and mortality compared with non-diabetics the threshold for treating blood pressure and lipids with drug therapy should be lower. In coronary patients, selected prophylactic drug therapy is indicated in the form of aspirin, beta-blockers, ACE inhibitors and systemic anticoagulants which, together with lipid lowering drug therapy, have all been shown to reduce coronary mortality and improve life expectancy. When a patient presents with coronary disease, and particularly when there is a family history of premature coronary heart disease, the opportunity of screening first degree relatives should be taken with a view to primary prevention.