Inability to eat due to lung cancer can be caused by a variety of reasons, which should be improved by radiotherapy, stent implantation, nasogastric tube and intravenous fluid maintenance according to the causes. 1. Radiotherapy and stent implantation: if the patient is combined with mediastinal space-occupying lesions, which cause difficulty in eating due to swallowing obstruction, stereotactic radiotherapy can be applied to the mediastinal space-occupying lesions; if the tumor has metastasized or caused esophageal narrowing due to compression, esophageal stent implantation can be applied. 2. Nasogastric tube: generally applicable to patients with advanced stage of cancer, liquid food (such as rice paste, rice soup, etc.) can be injected into the patient’s stomach with a syringe through the nasogastric tube. 3. Intravenous fluid maintenance: Intravenous needle or peripheral vein can be used to insert central venous catheter to input fluids (e.g. 5% glucose, 10% glucose, glucose sodium chloride, etc.) and nutritional fluids (amino acid, fat milk, albumin, etc.) into the patient’s body through vein to maintain the basic vital signs of the patient. Lung cancer unable to eat needs to go to the hospital and be treated by the physician according to the patient’s condition, and the medicine should not be used indiscriminately.