The causes of vomiting in advanced lung cancer patients include: a. brain metastasis of lung cancer, increased intracranial pressure can cause vomiting, which can be treated with head radiotherapy and dehydration treatment of lowering cranial pressure such as mannitol, glycerol fructose and dexamethasone. Second, the application of chemotherapy drugs, due to chemotherapy drug side effects can cause vomiting, the application of chemotherapy antiemetic drugs, such as toltestrone, ondansetron and other drugs symptoms can be improved, chemotherapy will gradually disappear after the end of vomiting symptoms. Third, the patient is bedridden for a long time, bowel obstruction can also cause nausea, vomiting, gastrointestinal decompression and water fasting, vomiting symptoms can be relieved after the smooth passage of stool. Electrolyte disorder will also cause vomiting, so blood should be drawn to check electrolytes and medication should be used according to the results. Therefore, there are many reasons for vomiting in advanced stage of lung cancer, and further examination is needed to clarify the cause and then use the right medicine.