1.What cases need medical thoracoscopic treatment? For patients with unexplained pleural effusion, especially those who cannot be clearly diagnosed by repeated pleural fluid examination, it is necessary to perform endoscopic thoracoscopy and biopsy for pleural lesions to facilitate diagnosis. 2.What is the role of endoscopic thoracoscopic treatment? What problems can be solved? Endoscopic thoracoscopy is a minimally invasive test that can be used firstly for the diagnosis of unexplained pleural effusion or pleural lesions, and secondly for diffuse or peripheral type confined lung lesions, which can also help in the diagnosis when the cause cannot be determined by other examination methods. For patients with malignant pleural effusion and poor drug treatment, talc pleural fixation as well as removal and drainage of acute abscess pleural adhesions and treatment of pneumothorax can be performed by endoscopic thoracoscopy. 3.Can endoscopic thoracoscopy be used as a routine treatment for pleural effusion? About 40% of malignant pleural effusions can be diagnosed clearly by sending cytology after thoracentesis and pleural fluid drainage, but some pleural effusions that cannot be diagnosed clearly by pleural fluid cytology can be diagnosed clearly by pleural biopsy under medical thoracoscopy. 4.Which patients are not suitable for thoracoscopic treatment? Contraindications to medical thoracoscopy: patients with extensive adhesions in the pleural cavity, abnormal coagulation function, cardiopulmonary insufficiency, severe pulmonary hypertension or pulmonary venous congestion and patients who cannot tolerate the procedure. 5.What are the common complications and how to prevent and deal with them? Complications of internal thoracoscopic surgery mainly include: bleeding, infection, pneumothorax, air embolism, pulmonary edema after pulmonary reopening, etc. Strict grasp of surgical indications and contraindications, standardized surgical operation and careful postoperative observation can help avoid complications.