necrotizing enterocolitis is a dangerous disease that may be fatal especially in preterm neonates, the early features of the disease are symptoms of feeding intolerance and interruption of the baby's feeding plan , so prophylactic measures at this stage may help to prevent its progression and its complications.

N-acetyl cysteine is an FDA- approved drug and has many uses in different diseases and in different age groups including neonates, it has a mucolytic and anti-inflammatory and anti-oxidant effects that are believed to break the bacterial biofilm which enables it to stick to the intestinal wall and also decrease the intestinal wall inflammation, therefore enhance the intestinal barrier and decrease the chance of bacterial invasion.

Inclusion Criteria:

• preterm neonates (less than or = 36 weeks gestational age )
• feeding intolerance

Exclusion Criteria:

• active gastro-intestinal tract bleeding
• Gastro- intestinal tract surgical problem
• Congenital gastro-intestinal tract anomalies
• evidence of allergy to NAC
• use of prebiotics or probiotics

for patient confidentiality