This book focuses on statins which are a relatively new group of drugs used to lower blood cholesterol levels. A high cholesterol level increases a person's risk of having a heart attack or stroke. The long-term use of statins reduces the risk of such an event and can increase the life expectancy of people with a history of heart disease. The statins work by blocking an enzyme in the body that is involved in the production of LDL cholesterol, especially in the liver. This enzyme is known as HMG coenzyme A reductase. The statins are the most effective group of drugs for lowering the levels of LDL cholesterol in the body. Potential side-effects include muscle cramps and gastrointestinal upsets. These are usually resolved on temporarily lowering the dose. Liver enzyme derangements may occur, which generally return to normal after briefly discontinuing the drug. Some report headaches. Other side-effects occur rarely.