Maintaining body cholesterol homeostasis is critical for normal physiological functions and is achieved by a highly regulated balance of de novo synthesis, dietary cholesterol absorption, biliary clearance, and excretion. The mechanisms controlling cholesterol absorption are important to understand for the prevention and treatment of hypercholesterolemia. Cayman’s Cholesterol Uptake Cell-Based Assay Kit provides a convenient tool for studying cholesterol absorption modulators. The kit employs NBD Cholesterol, a fluorescently-tagged cholesterol, as a probe for the detection of cholesterol taken up by cultured cells. U-18666A, a cholesterol intracellular trafficking inhibitor, is included as a positive control.