Numerous theories have been proposed to explain the pathogenesis of necrotizing enterocolitis (NEC). Current evidence suggests that injury to the intestinal barrier as a result of various perinatal insults may facilitate invasion of the intestinal wall by bacteria. An inflammatory cascade ensues, characterized by local release of various cytokines that may contribute to further tissue destruction and hemodynamic instability in NEC. Molecular biological probes show increased expression of inducible nitric oxide synthase and interferon-gamma in the intestine of infants with NEC. Studies are planned to define the role of these inflammatory mediators in a rat model of NEC.