Much diverse evidence suggests that the plasma levels of low-density lipoprotein (LDL) cholesterol play a causal role in the pathogenesis of atherosclerotic coronary heart disease. Until recently, clinical trials of LDL lowering, while showing significant reductions in coronary heart disease (CHD) rates, were not entirely convincing and left some questions of long-term toxicity unresolved. The results of a series of new trials using members of the powerful statin class of drugs are now being reported. Whether they are primary or secondary prevention studies, they have been uniformly successful in reducing mortality and morbidity from CHD and even total mortality, and have decreased the need for revascularization procedures. Their effectiveness is apparent in many different subgroups such as women, diabetics, hypertensives, and in stroke prevention. Statin drugs also have proven to be remarkably safe over the duration of the studies. Angiographic studies show an impact on coronary or carotid lesions.