Treatment with HMG-CoA reductase inhibitors (or statins) lowers total and LDL cholesterol and decreases the risk of cardiovascular events. The absolute benefits are greater in patients with a higher baseline cardiovascular risk, so statins are particularly suited to secondary prevention. Although three large studies have shown convincingly that, in patients with a history of cardiovascular disease, simvastatin or pravastatin treatment reduces the risk of further events and lowers overall mortality, those studies have not included patients in the period immediately after an acute coronary event. They are, therefore, of limited value in answering the question of when to start statin treatment. However, there are practical reasons for starting statin treatment as early as possible, and results of clinical studies have now shown this to be a safe option for pravastatin. Early treatment with pravastatin can stabilize coronary atherosclerosis and improve endothelial function. More importantly, there is also evidence that early treatment with pravastatin can produce a clinical benefit a few months after the initial coronary event. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.