Long-term complications of hyperglycemia are well known, but short-term complications are not. Because hyperglycemia and hypoglycemia can be corrected relatively rapidly, it seems important to determine if such interventions during acute illnesses improve patient outcomes. In most animal stroke studies, animals with hyperglycemia before or during brain ischemia have worse outcomes than those with normoglycemia. In humans, hyperglycemia during acute stroke has been associated with worse clinical outcomes than normoglycemia, but it remains to be established if rapid correction of the hyperglycemia will improve patient outcomes. Intravenous insulin infusion protocols are the only currently established methods to effectively lower and control hyperglycemia during acute illness. Recent pilot clinical trials demonstrate feasibility and safety of such interventions. One randomized efficacy trial has been reported and additional trials are needed. In the meantime, an intermediate approach to managing acute stroke hyperglycemia with subcutaneous insulin seems reasonable.