The reasons for vomiting when eating in the late stage of lung cancer are as follows: 1. nausea and vomiting may be caused by gastrointestinal reactions and indigestion; 2. anti-tumor treatment, whether radiotherapy, chemotherapy or targeted drug therapy, may cause gastrointestinal side effects, that is, nausea and vomiting, which can be treated with antiemetic drugs to reduce the reaction; 3. If patients have other electrolyte disorders, vomiting may also occur; 4. Patients with lung cancer need to be alert to the possibility of vomiting caused by increased intracranial pressure, that is, intracranial lesions, such as cerebrovascular lesions or brain metastases of lung cancer, etc., and need to cooperate with cranial MRI to assist in diagnosis.