Cholesterol absorption and synthesis are inter-regulated, so if one changes then the other changes in the opposite direction. The regulation and detailed mechanism of cholesterol absorption have been intensely investigated. Inhibition of cholesterol absorption has become an additional factor for cholesterol lowering. Agents inhibiting cholesterol absorption, mainly plant stanols and sterols or ezetimibe, usually lower low-density lipoprotein cholesterol in monotherapy by less than 20%, indicating that these inhibitors can normalize cholesterol levels only in patients with a modest baseline hypercholesterolemia. Body weight, especially obesity with and without diabetes, and dietary plant sterols alter cholesterol absorption differently. This article briefly reviews some special questions of cholesterol absorption under these conditions.