The differences between breast milk and infant formulas have been a popular subject of many recent studies. Most concern the chemical and biological characteristics of breast milk and infant formulas, but little work has been done about hemodynamic changes in the splanchnic circulation. In term neonates (n=22) we evaluated the effect of breast milk, adapted cow's milk formula, and nucleotide supplemented cow's milk formula on intestinal blood flow. To determine the blood flow velocity and estimate volume flow, pulsed Doppler ultrasound of the superior mesenteric artery (SMA) was performed prefeeding and 15, 45, and 90 minutes following feeding. When pre-and postprandial blood flow features of babies were compared among in their groups according to nutrition post prandial blood flow velocity and volume flow were increased significantly over baseline in all three groups. While there was no significant difference between the postprandial blood flow parameters of the breast milk and adapted cow's milk formula-fed groups, the nucleotide supplemented cow's milk formula-fed group had significantly higher postprandial blood flow velocity and volume flow. © 1994 Dr. K C Chaudhuri Foundation.