The use of fibrinolytics for the percutaneous drainage of loculated pleural effusions has been shown to reduce the catheter dwell time and to improve drainage of the effusions. Abscesses in the abdomen and pelvis are often loculated which makes percutaneous drainage difficult. We hypothesize that the infusion of alteplase via a drainage catheter into the loculated abscess collections of the abdomen and pelvis will similarly decrease catheter dwell time and improve overall abscess drainage. The direct injection of Activase into abscess cavities utilizes a very low dose of drug within a closed environment which should not be associated with any significant risk of hemorrhage. To date, there does not appear to be a significant risk of systemic hemorrhagic complications associated with the use of intracavitary thrombolytics for the drainage of abdominopelvic abscesses although only a few such studies have been reported. We hope to prove that the use alteplase for intracavitary thrombolysis improves outcomes associated with percutaneous catheter drainage of loculated abscess collections without increasing complications or costs.