Hypercholesterolemia, or high cholesterol, occurs when there is too much cholesterol in the body. Cholesterol is a component of all cells within the body. The body makes all the cholesterol it needs. High cholesterol raises the risk for heart disease and stroke. Too much cholesterol can form plaque, which can “stick” along the artery walls. Plaque can eventually narrow or block the flow of blood to the brain, heart, and other organs.