Evidence is accumulating that diets low in saturated fatty acids and high in monounsaturated fatty acids are effective in controlling blood lipid levels; a likely consequence could be a beneficial effect on the risk of coronary heart disease. Although as yet limited in number, studies have shown monounsaturated fatty acids to be the equivalent of polyunsaturated fatty acids or low-fat diets in lowering blood low-density-lipoprotein cholesterol. The monounsaturated acids apparently have the added advantage of not causing a decrease in high-density-lipoprotein cholesterol or an increase in blood triglycerides, which can be a consequence of other dietary modifications. In the past, olive oil was the only fat rich in monounsaturated acids that was generally available in the United States. Recently, canola oil, a fat also rich in monounsaturates, has appeared in retail food outlets. Other potential sources are high oleic sunflower and safflower oils. Because the culinary and organoleptic properties of the monounsaturated-rich oils can be identical to those of currently used oils, they should be readily accepted by the consumer. Whether the preferred healthful diet is one low in fat or one high in monoenes or polyenes, the primary dietary recommendation remains--decrease the intake of saturated fat and cholesterol.