Pulmonary embolism (PE) is life threatening disease requiring early diagnosis and treatment. Thrombolytic therapy (TT) is required in patients with massive PE. PE has a high mortality but the in-hospital all-cause case mortality rates were lower in unstable patients who received TT than those who did not. However, it was reported that minority (nearly 30%) of unstable patients received thrombolytic therapy. The reason that majority of unstable patients failed to receive thrombolytic therapy is unclear. The higher rates of complications including the life threatening bleeding may be a reason of reluctance in the use of TT.