Elderly people have diarrhea, and the cause of blood in the feces, depending on the way of bleeding, the amount of bleeding, and the color, as follows: 1, hemorrhoids or anal fissure: if the yellow stool, accompanied by a small amount of blood or dripping blood, consider hemorrhoids or fissure caused by anal fissure. 2, ulcerative colitis or acute bacillary dysentery: if the diarrhea accompanied by mucus pus and blood stools, the amount of small times, accompanied by the rapid and then severe, consider ulcerative colitis or acute bacillary dysentery. 3, acute gastroenteritis: if the fiber yellow stool, followed by complete blood stool, bright red, dark red, considering acute gastroenteritis, mucosal erosion, bleeding caused by gastrointestinal bleeding. 4, other causes: if the whole process of blood stool, dark red or red, suggesting that the amount of gastrointestinal bleeding, commonly found in acute erosive and hemorrhagic gastritis, gastric ulcers, gastroduodenal disease, rupture of esophageal varices bleeding, or gastric cancer, this time the condition is serious. The condition is serious at this time. When patients have diarrhea and blood in the stool, they should go to the hospital in time for systematic examination to clarify the cause of bleeding, the amount and location of bleeding, and then give comprehensive treatment such as hemostasis and protection of gastrointestinal mucosa.