Black mud stool after total gastrectomy may be caused by physiological reasons such as diet, which is a normal phenomenon; it may also be caused by reflux esophagitis, gastrointestinal bleeding and other pathological reasons, which is not normal. 1. Physiological reasons: overeating, consuming cold, greasy, spicy and irritating food such as spicy hot, fried chicken, alcohol, strong tea, ice cream, marinated meat, etc., can increase the burden on the stomach and intestines, stimulate the gastrointestinal mucous membrane, and cause symptoms such as black sludge stools, gastric pain and stomach distension after total gastrectomy. 2. Pathologic causes: (1) Reflux esophagitis: it is a common complication after total gastrectomy, manifested as nausea, vomiting, acid reflux, heartburn and other symptoms. (2) Gastrointestinal bleeding condition: it may be bleeding caused by poor wound healing or wound dehiscence after surgery, or new gastrointestinal bleeding diseases may occur, such as ulcerative colitis, colon polyps and other diseases. Black sludge stool after total gastrectomy is recommended to seek immediate medical attention and targeted treatment under the guidance of a doctor.