Aim: To discuss intestinal side effects of ibuprofen in the treatment of patent ductus arteriosus, after having observed two cases of spontaneous intestinal perforation following ibuprofen treatment. Methods: Clinical and laboratory records of two preterm infants, who developed intestinal perforation after ibuprofen administration, were evaluated. Results: Gestational ages of infants were 29 wk (male) and 30 wk (female). Both infants developed intestinal perforations without signs of necrotizing enterocolitis. The perforations cured with Penrose drainage alone.