The difference between pulmonary embolism and pulmonary edema lies in their mechanisms of onset, clinical manifestations, and treatments; they are completely different diseases. Pulmonary embolism primarily occurs when thrombi from the inferior vena cava or superior vena cava, or other emboli, travel with the bloodstream to the right heart and then block the pulmonary artery. The symptoms mainly include coughing, chest pain, difficulty breathing, and coughing up blood. On the other hand, pulmonary edema is mostly due to left heart dysfunction, caused by coronary artery disease or acute heart failure, leading to the inability of the pulmonary blood to return to the left heart. This results in an excessive retention of blood in the lungs, causing edema in the alveoli and interstitial space of the lungs. The symptoms are primarily characterized by difficulty breathing, coughing, and pink frothy sputum. The treatments for the two are also entirely different: pulmonary embolism is primarily treated with thrombolysis, while pulmonary edema is mainly treated by correcting heart function. Thus, it is crucial to differentiate between these two diseases.