Hypercholesterolemia is a condition by which the serum cholesterol levels in the body are above normal values. Cholesterol is a fatty substance found in all animal tissues and makes up an important part of cell membranes. The liver uses cholesterol to manufacture bile. Cholesterol is used to produce certain hormones, including sex hormones. The body manufactures its own cholesterol, but it also absorbs it through fatty foods. When cholesterol levels become too high, the excess cholesterol is deposited as fatty plaque on the interior walls of the arteries, which can lead to blockages.

Total serum cholesterol levels are monitored as well as the amount of specific types of cholesterol transport molecules. High-density lipoproteins (HDL) are sometimes called "good cholesterol" because it may actually provide protection from heart attacks. Conversely, low-density lipoproteins (LDL) have been linked to certain diseases, particularly atherosclerosis.

Risk Level Serum Cholesterol LDL Level
Low risk <200 <130
Borderline 200-239 130-159
High Risk >240 >160
Risk Level
Male Female
Decreased Risk <72 <96
Average Risk 52 68
Increased Risk >32 >39

Lowering total serum cholesterol levels and reducing LDL are desired goals. Most frequently, modifying one's diet so that no more than 30 percent of calories are derived from fat is a first step. Aerobic exercise has been shown to reduce serum cholesterol levels and boost HDL ("good cholesterol") levels. Avoiding smoking and alcohol abuse tends to help lower cholesterol levels as well. When these steps are insufficient, medications may be prescribed.