Hyperlipidemia is the medical name for high cholesterol. 

Cholesterol is a lipid, a fatty substance mainly produced by the liver also found in some foods. While important for the natural functioning of the body, excessively high levels can have an adverse effect on health and increase the risk of more serious health conditions developing. 

Cholesterol is carried by proteins in the blood, which together make lipoproteins, of which there are high-density and low-density forms. High-density lipoproteins carry cholesterol back to the liver, where it can be broken down or excreted as waste. Low-density lipoproteins carry cholesterol back to the cells and high levels can be dangerous as excess cholesterol builds in the artery walls, resulting in arterial disease. 

Causes of high cholesterol include smoking, history of heart disease or strokes in the family, an unhealthy diet with lots of saturated fat, and smoking. It may also be a sign a patient has another condition, such as diabetes or high blood pressure. 

Part of treatment for patients with high cholesterol levels involves lifestyle changes, such as adopting a better diet, getting more exercise and quitting smoking. Medication is also used to lower cholesterol levels. Doctors may prescribe HMG-CoA reductase inhibitors, more commonly known as 'statins', such as Lipitor (atorvastatin), Crestor (rosuvastatin) and Zocor (simvastatin).