When vomiting after eating in the advanced stage of lung cancer, it is necessary to clarify what is the etiology of the patient’s vomiting. Generally, the first common one is brain metastasis of lung cancer. The patient has brain metastasis, intracranial edema, large edema of brain cells, resulting in increased intracranial pressure, and the patient has nausea and vomiting with headache and dizziness. Treatment is mainly with dehydration drugs, such as mannitol, glycerol fructose dehydration symptomatic treatment, which can relieve vomiting. Secondly, if intestinal obstruction occurs due to metastasis of abdominal organs or lymph nodes, slow intestinal peristalsis and gas evacuation will show nausea, vomiting, and even abdominal pain and difficulty in venting and defecation. Therefore, the cause of vomiting should be clarified and the patient should be treated accordingly in order to relieve it.