Drowsiness in late stage of gastric cancer is mainly due to hepatic encephalopathy and nutritional absorption, which is a bad manifestation, and some patients may be caused by drug effects. 1. Hepatic encephalopathy: when cancer cells metastasize to liver, it will lead to damage of liver function, resulting in hepatic encephalopathy. At this time, toxins accumulate in the brain due to liver failure, which will damage brain cells and cause drowsiness of patients. 2. Nutritional absorption is affected: cancer cells in the late stage of gastric cancer spread to all organs of patients, affecting the normal work of body organs, resulting in poor nutritional absorption and metabolism and malaise, causing extreme malnutrition of patients, thus resulting in the symptom of drowsiness. 3. Role of drugs: most stomach cancer patients will take a lot of painkillers in the late stage, which will also lead to drowsiness. Patients with advanced stage of gastric cancer must consult doctor in time and take active treatment when drowsiness occurs, so as to improve the quality of life and prolong the survival period.