Diarrhea for a month consider the following three factors: First, chronic intestinal diseases: such as ulcerative colitis, intestinal tuberculosis, intestinal tumors, Crohn’s disease, etc. Second, extra-intestinal factors: such as chronic hepatitis, cirrhosis, liver cancer, cholecystitis, pancreatitis, pancreatic tumors, diabetes, hyperthyroidism, can cause fast intestinal peristalsis, diarrhea, and possibly steatorrhea. Third, psychological and mental factors: such as gastrointestinal neurosis, mental stress, irritable bowel syndrome caused by environmental changes. When there is a change in the nature, color and bowel habits of the stool, we should pay attention to further examination of gastroscopy, abdominal CT or intestinal barium angiography to clarify the cause and give comprehensive treatment to avoid delaying the disease.