Necrotizing enterocolitis (NEC) has a multifactorial etiology, an incompletely defined pathogenesis, and predominantly affects neonates with severe, necrotizing injury to the intestine. Because the underlying clinical circumstances are not uniform, NEC may represent a syndrome, with common findings and a variety of etiologies. The uniform morphology of the well-established intestinal lesions, representing a latestage response, is consistent with a common pathogenesis. Discrepant etiologies are possible. Necrosis of the intestine can occur at any age following the sudden, complete occlusion of the blood supply to the bowel. In the newborn, thromboemboli secondary to the use of intravascular catheters may cause bowel infarction. However, since neonatal NEC cannot be traced to thromboemboli, it is considered nosologically distinct from bowel infarction in older patients. Therefore, in the following discussion NEC is understood to exclude cases of bowel infarction associated with thromboembolic lesions. NEC remains a leading cause of morbidity and mortality in neonatal intensive care units, with a reported incidence of 10.1% among very low birthweight infants (1500 g)[1], and a mortality of 26%[2]. A disease of serious prognosis, advanced cases of NEC may cause multisystem organ failure [3]. Of the 2500 cases occurring annually in the United States [4, 5], 20%–60% require surgical treatment [6]. At least 80% of patients are preterm, or have low, or very low birthweight, and the incidence of the disease is inversely proportional to the gestational age [4, 7, 8]. Advances in the supportive care of premature babies, such as use of surfactant, improved technologies for mechanical ventilation, and wider availability of skilled personnel, enable the very premature to survive, and in so doing increase the population of patients susceptible to NEC. Thus, it may be that medical advances constitute, paradoxically, one reason for the rising incidence of NEC. Infants of extremely low birthweight (under 1000 g) and those 28 wk or less of gestational age are at greater risk of NEC than infants closer to term at birth. The severity of the disease and attending complications are greater in infants of extremely low birthweight with more extensive intestinal involvement and higher mortality [9].