The mechanism of action and clinical efficacy of lovastatin, simvastatin and pravastatin as hypolipidemic agents is reviewed. All three drugs act primarily in the liver and reduce plasma concentrations of low-density lipoprotein and very-low-density lipoprotein remnants by 30–50%. Serious side effects involving the liver or muscle are uncommon; the risk of myopathy is, however, increased when lovastatin is combined with gemfibrozil and this combination is not recommended.