If pleural effusion still appears after drainage of lung cancer pleural effusion, local medication in chest cavity or systemic medication can be used to control the condition. If pleural effusion caused by lung cancer belongs to malignant pleural effusion, it will often reappear after drainage and the treatment effect is not good, so it can be controlled by local medication and systemic medication: 1. Local medication: after drainage of pleural effusion, drugs such as elemene injection, interleukin-2, cisplatin, etc. can be injected into the chest cavity to control the growth of pleural effusion. 2. Systemic drugs: according to the pathological type of lung cancer, systemic chemotherapy can be used to control the disease if the patient’s physical condition permits. If the pathological type of lung cancer is adenocarcinoma, gene test is feasible. If the test result is positive, oral targeted drugs such as gefitinib, ectinib and crizotinib can be taken to control the condition and further control the growth of pleural effusion. If the pleural effusion of lung cancer is still recurring after drainage, it is recommended to consult with oncology specialists and choose appropriate treatment plan according to the condition.