There is no prognosis for diarrhea in the elderly; it may be a physiologic factor or a pathologic factor. Physiologic factors may be caused by an unclean diet. Pathological factors can be divided into acute diarrhea and chronic diarrhea. 1. Physiological factors: the elderly may have diarrhea because of unclean diet, and there will be obvious diarrhea and other phenomena, usually without special treatment, and can be recovered soon. 2. Pathological factors: divided into acute diarrhea and chronic diarrhea, acute diarrhea, including viral infections, bacterial infections, parasitic infections, and drug factors. Chronic diarrhea is more complex, including intestinal infectious diseases, intestinal non-infectious diseases, small intestinal malabsorption, gastrointestinal power disease and so on. Senior citizens with diarrhea, if it lasts for a few days without relief, diarrhea is still severe, and the body is weak, the face is abnormal, please go to the regular hospital in time to receive treatment.