Vomiting when drinking water in late stage of stomach cancer may be caused by large tumor, intestinal obstruction, tumor invading esophagus, and patients can be treated by chemotherapy and surgery. 1. Large tumor: the tumor is often large in the late stage of stomach cancer, which may cause occupying lesions in most or all of the stomach, leading to severe vomiting. Patients can undergo chemotherapy by using chemotherapeutic drugs, such as paclitaxel oxaliplatin, under the guidance of doctors to shrink the lesions and relieve the symptoms of vomiting. 2. Intestinal obstruction: severe vomiting in late stage of gastric cancer may also be caused by intestinal obstruction caused by tumor, and patients can have the obstruction part removed by gastrointestinal short-circuit surgery, so as to alleviate the symptom of severe vomiting. 3. Tumor invading esophagus: after the tumor invades the esophagus, the patient may also suffer from severe vomiting. The patient can remove the diseased esophagus through surgery to alleviate the symptom of vomiting and difficulty in eating. Patients with advanced stage of stomach cancer should have timely treatment when they are not feeling well, so as to prolong their life.