The results of liver function tests indicate low total protein, which can be seen in patients with insufficient food intake or chronic depletion, as well as in patients with malnutrition. In addition, patients with malignant tumors may also experience a decrease in nutritional indicators, mainly in the form of low protein levels, weakness and loss of appetite, especially in patients with malignant tumors of the intestinal tract, and chronic blood loss. Blood in the stool, black stool, and even massive gastrointestinal bleeding are all causes of protein decline. Therefore, a targeted treatment plan should be chosen according to the condition. Patients with insufficient intake can be supplemented with high-protein foods; while patients caused by malignant tumors should undergo early surgery and, if necessary, intravenous chemotherapy to control the development of the tumor.