Reducing cholesterol and LDL cholesterol (LDL-C) is one of the few clearly demonstrated principles in the prevention and treatment of arteriosclerosis. LDL-C reduction over a number of years to ca. 70 mg/dl can reduce the risk of coronary events by about two thirds. Lipid lowering pharmacotherapy is the more effective the higher the individual risk of the patient is. The therapeutic decision is based on the total risk of the patient. For coronary patients after acute coronary syndrome and/or with diabetes mellitus, a reduction of LDL-C to 70 mg/dl is justified. For patients with "stable" coronary heart disease, a LDL-C level of 100 mg/dl or less should be strived for. Whether diabetes mellitus always indicates a "coronary risk equivalent" and thus justifies a reduction in LDL-C to 100 ml/dl or less, is questionable.