The efficacy of a bovine surfactant preparation (SF-RI 1) to increase survival without bronchopulmonary dysplasia (BPD) was studied in very premature infants in a multicenter, randomized sequential trial. Thirty-four infants were randomized to surfactant treatment, whereas 35 infants served as controls. As part of the study, pharmacotherapy with antibiotics, sedatives, catecholamines, diuretics, methylxanthines, mucolytics, muscle relaxants,digoxin, and indomethacin was registered during week 1 and weeks 2-4. As to the endpoint of the study a significantly increased survival rate without BPD was observed in surfactant-treated infants (76%) compared to controls (40%). Significant differences concerning drug utilization were found through week 1 with increased use of methylxanthines in surfactant-treated infants, which persisted during weeks 2-4 as well as a reduced incidence of diuretic therapy in surfactant-treated infants during weeks 2-4. These differences may be attributed to the shorter interval of mechanical ventilation in surfactant-treated infants (11 days) compared to controls (27 days), and to the above mentioned increased survival rate without BPD.