Objective: Proper antibiotic treatment and adequate pleural drainage is essential in successful management of pleural effusions. In complicated effusions the increased production of fibrin results in formation of loculations and septations within the thoracic cavity, leading ineffective chest tube drainage. Intrapleural fibrinolytic agents are employed to avoid thoracotomy in such complicated pleural effusions. Our study reviews the results of streptokinase treatment in children with pleural effusion. Methods: Thirty-two patients with parapneumonic pleural effusions were admitted to our hospital. The patients beyond the exudative stage were divided into two groups according to the initial radiological findings and biochemical parameters of pleural fluid. Intrapleural streptokinase treatment was started in an average of 2 days following initial chest tube placement in both Group I (14 patients) in fibrino-purulent phase with pleural effusion and fluid volume estimated to be larger than one-third of the involved lung and Group II (18 patients) with additional findings in radiological examination regarding the presence of air-fluid levels, multiple loculations, necrotic debris and pleural thickening. The effectiveness of therapy was assessed by monitoring the volume of the fluid, the level of LDH, glucose, pH and by radiological imaging, pre- and post-instillation. Results: There was statistically significant difference between two groups according to date of admission (6.8 vs 10.4 days), mean of total pleural fluid drainage before (106.9 vs 309.7 ml) and after (258.9 vs 511.2 ml) SK treatment, mean of total number of instillations (2.1 vs 3.6) required and total length of hospital stay (16.6 vs 22.4 days). There was a significant difference regarding pleural chemical analysis. Finally, surgical intervention was necessary in six intractable cases, all of which initially presented a significant small amount of pleural drainage in volume when compared to rest of the patients. The overall success rate of our treatment was calculated as 96% for G-I and 72.2% for G-II cases. Conclusions: Intrapleural streptokinase is an effective and safe adjunct in facilitating drainage in early and late stage II empyemas. A tendency of decreased rate of drainage besides persisting fever and respiratory symptoms, despite fibrinolytic treatment may be a clue for early surgical intervention. (C) 2004 Elsevier B.V. All rights reserved.