Aggressive treatment of atherosclerotic risk factors can substantially reduce stroke risk in patients with a history of stroke or transient ischemic attack. Data from several recent large clinical trials provide convincing evidence of benefit for a number of specific therapies directed at this population. The authors recommend treatment with ramipril alone or perindopril plus indapamide regardless of blood pressure, provided there is no contraindication. For patients already taking a different angiotensin- converting enzyme (ACE) inhibitor, the authors do not routinely switch agents. The authors recommend use of simvastatin 40 mg per day in patients with a total cholesterol level of 135 mg/dL or greater, provided no contraindication exists. The authors also recommend consideration of gemfibrozil in patients with isolated low high- density lipoprotein levels. In patients with diabetes mellitus, tight glycemic control has not been shown to reduce macrovascular complications such as stroke, but does reduce microvascular complications. However, diabetics should receive especially aggressive treatment of other vascular risk factors. There is no role for post-menopausal hormone replacement therapy in prevention of stroke. Weight loss for overweight patients, regular exercise, and a diet rich in fruits, vegetables, cereals, and fish, as well as low in fat and cholesterol, should be a standard recommendation for this group of patients. Treatment with folic acid, B(6), and B(12) for patients with elevated homocysteine appears rational, though this is unproven. However, there is no benefit to vitamin E, vitamin C, or beta-carotene supplementation. Smokers should stop. For every 43 smokers who quit, one stroke is prevented. Moderate consumption of alcohol (one to two drinks a day) may be beneficial, but heavy alcohol use (more than five drinks a day) increases stroke risk.