NEC is one of the most common ,deadliest and enigmatic intestinal problems encountered mostly in premature infants. The precise pathophysiology of NEC is unclear ,but major factors thought to play an important role include an immature intestine ,an inflammatory response to intestinal microbes,enteral feedings and intestinal ischemia-reperfusion injury.Diagnosis of NEC is not easy clinically and up to now there is not a simple laboratory test to differentiate NEC at an early stage from other conditions in the neonate.