Both alone and in combination with other lipid-lowering drugs, the bile acid sequestrants cholestyramine and colestipol, are excellent agents for lowering circulating low-density lipoprotein (LDL) cholesterol levels. They have been shown to lower the incidence of new coronary events and to retard the progression of coronary atherosclerosis. They also induce qualitative changes in lipoproteins whose significance requires further investigation but may be of significance in coronary disease prevention. While side effects may be bothersome for some patients, they can generally be managed effectively. In particular, modest lowering of dosage may preserve considerable LDL cholesterol lowering and virtually eliminate side effects. Sequestrants appear to be among the safest and most effective drugs in the cholesterol-lowering armamentarium.