Abstract: Objective To study efficacy and safety of combined thoracic urokinase infusion and local chemotherapy for encapsulated malignant hydrothorax. Methods Eighty-two patients with encapsulated malignant hydrothorax were divided into treatment group(n=42) and control group(n=40).Patients in treatment group were treated by thoracic infusion of 200 000U urokinase(twice a week) followed by thoracic infusion of bleomycin and interleukin-2 while those in control group were treated by direct infusion of bleomycin and interleukin-2 after all dropsy was drained from thorax with a thorax-dwelling tube.Their clinical outcome was assessed two weeks after chemotherapy.Activated partial thromboplastin time(APTT),prothrombin time(PT),thrombin time(TT),and fibrinogen(FIB) in treatment group were detected before and after treatment. Results The excellent and good clinical outcome was achieved in 10 and 17 patients of treatment group respectively with a total effective rate of 64.3%,and in 2 and 11 patients of control group respectively with a total effective rate of 32.5%(P<0.05).No significant difference was found in the APTT,PT,TT,and FIB of treatment group(P>0.05) and no severe complications such as thorax and systemic bleeding occurred in two groups. Conclusion Combined thoracic urokinase infusion and local chemotherapy is an effective and safe treatment modality for encapsulated malignant hydrothorax.