Frequent vomiting in advanced stage of lung cancer may be caused by adverse reaction of chemotherapy drugs, hypokalemia, brain metastasis of cancer cells, and it is necessary to take medication and radiotherapy for the cause of the disease. 1. Adverse reaction of chemotherapeutic drugs: patients with advanced lung cancer treated with chemotherapeutic drugs may have gastrointestinal adverse reactions such as nausea and vomiting, and it is suggested to use antiemetic drugs such as ondansetron and granisetron under the guidance of doctor. 2. Hypokalemia: patients with advanced stage of lung cancer may suffer from water-electrolyte disorders, and nausea and vomiting may occur if they suffer from hypokalemia. At this time, it is necessary to follow the doctor’s instruction to give potassium chloride, potassium citrate and other potassium agents to patients. Some patients can also take surgical treatment such as removing adrenal tumor and pituitary tumor. 3. Brain metastasis of cancer cells: metastasis of cancer cells to the brain in advanced stage of lung cancer may lead to increased intracranial pressure, which may easily cause projectile vomiting. For patients with increased intracranial pressure, they can use diuretics such as mannitol and glycerol fructose as prescribed by doctors, and some of them can also be treated by irradiating the brain with radiation. Frequent vomiting in late stage of lung cancer may also be caused by intestinal obstruction and liver metastasis of lung cancer. It is suggested that lung cancer patients with frequent vomiting in late stage need to consult doctor in time, and doctor will choose appropriate measures to treat the cause of the disease.