The purpose of this study was to evaluate the feasibility of the use oral ibuprofen suspension (OIS) in the treatment of patent ductus arteriosus (PDA) in premature infants. Premature infants (</= 35 weeks) age 2 to 7 days who suffered from respiratory distress and had been diagnosed with PDA were included in this study. Color Doppler echocardiography (ECHO) was used to measure the internal ductal diameter, pressure gradient, and the ratio of left atrial to aortic root diameters (La/Ao). Infants were randomly assigned to one of two groups: group I received three doses of intravenous (IV) indomethacin (0.2 mg/kg at 12-hour intervals) and group O received an initial dose of OIS (10 mg/kg), followed by two doses of 5 mg/kg each, after 24 and 48 hours. A follow-up ECHO was done after treatment by the same pediatric cardiologist who was blinded to the assignment of the study groups. Changes in blood platelet count, hematocrit, blood urea nitrogen, and creatinine were compared between groups. In total, 78 premature infants were screened: 21 had been diagnosed with PDA. Infants in group I (n = 9) and group O (n = 12) did not differ in birthweight (1884 +/- 485 versus 1521 +/- 398 g [mean +/- SD]; P = 0.13), gestational age (32.9 +/- 1.6 versus 31.2 +/- 2.5 weeks; P = 0.07), internal diameter of PDA (2.3 +/- 0.5 versus 2.1 +/- 0.5 mm; P = 0.34), pressure gradient across PDA (12.83 +/- 6.46 versus 11.11 +/- 4.5 mm Hg; P = 0.48), and La/Ao ratio (1.26 +/- 0.21 versus 1.17 +/- 0.12; P = 0.25). Closure of PDA was achieved in 78% (seven of nine) of infants in group I and in 83% (10 of 12) of infants in group O. Comparisons of laboratory changes following treatment in group I and group O were as follows: decrease in hematocrit (-6.5 +/- 6.6 versus -1.2 +/- 4.2; P = 0.04) and in platelet count (-54 +/- 67 versus -1 +/- 53 x 10 (3)/muL; P = 0.24), and increase in blood urea nitrogen (16.4 +/- 16.4 versus 2.1 +/- 17.4 mg/dL; P = 0.06) and serum creatinine (0.12 +/- 0.22 versus -0.06 +/- 0.19 mg/dL; P = 0.13). Two infants in group I had severe pulmonary hemorrhage, whereas there were none in the group O. Oral ibuprofen could be an easy-to-administer and efficacious alternative in the treatment of PDA.