Diminished mucosal mass and a diminished rate of DNA synthesis by the intestinal mucosa have been identified in the rat after thermal injury. Because these changes may be associated with ischemia, the distribution of intestinal blood flow was studied after a thermal injury and compared with the blood flow distribution after hemorrhagic shock. For the thermal injury, anesthetized animals received a standardized 20% body surface area, full-thickness injury and were given intraperitoneal saline resuscitation. By the use of 46Sc- or 141Ce-labeled microspheres, no changes in intestinal and hepatic blood flow occurred after thermal injury. In contrast, a marked redistribution of blood flow was identified after hemorrhagic shock in which a decrease in arterial blood flow was identified to the stomach and to the small and large intestine. Although clinical shock was not present, the cardiac output decreased to a comparable degree in the hemorrhagic shock and the thermal injury. These studies indicate that although physiological changes in intestinal mucosa can be demonstrated after burn injury, these changes are not due to decreases in mesenteric arterial blood flow.