Pleural effusion implies suffering from inflammation of the lungs, tuberculous pleurisy, malignant tumors, heart failure, kidney disease, cirrhosis of the liver, and other diseases. Thorax refers to the cavity between the chest wall and the lungs. Pleural effusion means that excessive fluid has accumulated in the cavity of the organism, causing the patient to suffer from wheezing, chest tightness, shortness of breath, shortness of breath, and dyspnea. 1. Inflammation of the lungs, such as lung abscess, pneumonia, etc., may produce pyothorax or parapneumonic pleural effusion, which manifests as chest pain, cough, fever, coughing up sputum and other symptoms. 2. Tuberculous pleurisy, in which the effusion is mostly of medium to large volume, accompanied by symptoms such as night sweats, hot flashes, increased blood sedimentation, body wasting and coughing. 3. malignant tumors, such as lung cancer, advanced malignant tumors of gastrointestinal tract and lymphoma, etc., manifesting as large amount of pleural hemorrhagic effusion. 4. Heart failure, nephrotic syndrome mostly with pleural effusion on both sides, cirrhosis is often accompanied by abdominal effusion, and hypoproteinemia manifests as generalized edema and multiple plasma membrane cavity effusion. In short, patients with pleural effusion need to seek medical treatment in time, and after puncture, the relevant laboratory tests of pleural fluid are performed for diagnosis, and lung CT and tumor-related markers need to be examined to confirm the diagnosis.