Intravenous indomethacin and intravenous ibuprofen are widely used for the treatment of patent ductus arteriosus (PDA) in premature infants. Intravenous indomethacin may lead to renal impairment, enterocolitis, and intraventricular hemorrhage. Intravenous ibuprofen was shown to be as effective and to cause fewer side effects. If ibuprofen is effective intravenously, it will probably be effective orally, too. This study was conducted to test oral ibuprofen in early curative closure of PDA in very premature infants hoping for a better tolerance and the same efficacy as intravenous ibuprofen. Forty very premature infants (mean gestational age: 29.4 +/- 1 to 2 weeks [range: 26 to 31.5 weeks]; mean weight: 1237.2 +/- 198 g [range: 650-1770 g]) with PDA and respiratory distress were studied prospectively. They received, while between 48 and 96 hours old, oral ibuprofen at a dose of 10 mg/kg, followed, if needed, at 24-hour intervals by one or two additional doses of 5 mg/kg each. Color Doppler echography of the heart, brain, and abdomen were performed before treatment and after each dose administration. Ductal closure, early outcome (1 week after treatment), and late outcome were recorded. Thirty-eight patients (95%) achieved pharmacological closure. Two patients did not respond to the treatment: One required surgical ligation of the ductus, and the other patient received and well tolerated ductal shunting. Twenty-four patients were treated with one dose of oral ibuprofen, 10 were treated with two doses, and 6 were treated with three doses. Early outcome showed no case of renal impairment, no significant differences in serum creatinine levels, nine cases (22.5%) of intraventricular hemorrhage, three cases (7.5%) of necrotizing enterocolitis, and two cases (5%) of gastrointestinal bleeding. Late outcome showed 15 cases (37.5%) of nosocomial sepsis, 3 cases (7.5%) of chronic lung disease, 2 cases (5%) of periventricular leukomalacia, and 17 cases of death. In this study, oral ibuprofen was effective and well tolerated for early curative closure of PDA in very premature infants. Nevertheless, larger randomized comparative studies with pharmacokinetics measures are warranted.