Preterm infants commonly experience feeding intolerance, which can delay advancement of enteral feeding and impair early growth. This randomized double-blind controlled trial evaluated whether lactase enzyme supplementation could improve feeding tolerance and growth in Egyptian preterm infants born before 34 weeks of gestation. Infants were assigned to receive either feeds supplemented with lactase enzyme or standard feeds without lactase for 2 weeks from the start of enteral feeding. The study hypothesized that lactase supplementation would reduce signs of feeding intolerance and improve weight gain. Outcomes included feeding intolerance symptoms, stool markers of carbohydrate malabsorption, feeding progression, growth parameters, and selected clinical outcomes including necrotizing enterocolitis.