Controversy continues to surround the appropriate form and timing of nutrition support for the patient with circulatory shock. Clinical studies have demonstrated improvements in outcome with the administration of enteral nutrition to critically ill patients; however, the provision of enteral nutrition to critically ill patients with ongoing shock remains controversial. This article reviews gut perfusion during normal states and during circulatory shock as well as alterations in perfusion when enteral feeding is provided. Pharmaconutrients studied during ischemia and reperfusion are discussed.