Previously published data clearly demonstrate that hyperglycemia worsens morbidity and mortality in patients in intensive care, those with acute myocardial infarction and stroke, and those undergoing coronary artery bypass grafting. The control of hyperglycemia with insulin infusion improves clinical outcomes in these patients. In this article, we discuss data that demonstrate a proinflammatory effect of glucose and free fatty acids and an anti-inflammatory effect of insulin. We also provide a mechanistic justification for the benefits of maintaining euglycemia with insulin infusion in hospitalized patients.