There are indications that treatment of hypercholesterolemia by means of drugs reduce risk of atherosclerosis in patients with increased concentrations of atherogenic lipoproteins. Such therapy should be initiated only after satisfactory exclusion of secondary causes of hyperlipoproteinemia, and should be regarded as an adjunct to appropriate dietary therapy. Drug therapy should be strongly considered in patients with total cholesterol above 8-9 mmol/l on diet therapy only. Drug therapy should be considered at even lower concentrations of cholesterol when coronary heart disease is present and in familial forms of hyperlipidemia when increased risk of atherosclerosis has been documented. In patients with increased plasma concentrations of total cholesterol the drugs of choice are agents which enhance the rate of LDL catabolism (resins) or reduce the rate of LDL synthesis (nicotinic acid). Fibrates should be used when triglycerides and cholesterol are both increased. HMG CoA reductase inhibitors offer considerable promise in the therapy of patients with primary hypercholesterolemia. Probucol may be used in combination with other drugs, particularly when xanthomas are present in patients with familial hypercholesterolemia.