Colestipol is a safe, effective, cholesterol-lowering, bile-acid sequestrant that lowers low-density-lipoprotein (LDL) and total plasma cholesterol levels without consistently affecting high-density-lipoprotein (HDL) cholesterol levels. Long-term colestipol therapy in conjunction with diet may reduce xanthoma size, arrest progression of coronary artery atherosclerosis, and may reduce mortality from coronary heart disease. Probucol, a bisphenol cholesterol-lowering drug, is an effective cholesterol-lowering agent that reduces levels of HDL cholesterol, HDL cholesterol, and apoprotein A-1, the major apolipoprotein of HDL. Because HDL cholesterol is independently and inversely associated with development of coronary heart disease, the ramifications of simultaneous lowering of LDL and HDL cholesterol levels by probucol treatment need further study. Long-term, placebo-controlled studies of repetitive coronary arteriography, coronary heart disease morbidity and mortality, or both are needed to ascertain the efficacy of long-term probucol use in relation to development of atherosclerosis.