The common causes of vomiting in advanced cancer patients are as follows: 1) Gastrointestinal obstruction: common in primary tumors and metastatic tumors; 2) Metastatic tumors: invasion of the GI tract, resulting in GI tract discomfort; 3) Psychological factors: cancer patients are often combined with severe anxiety, depression and other psychological disorders; 4) Radiotherapy reactions: radiation therapy can cause radioactive mucositis, as well as highly emetogenic chemotherapy drugs, such as cisplatin, fluorouracil, paclitaxel, gemcitabine, oxaliplatin, etc.; 5) Electrolyte disorders: such as hypokalemia, resulting in abdominal distension and decreased appetite.