In general, coffee contains caffeine, but it does not cause diarrhea, and diarrhea when patients drink coffee may be caused by too cold coffee, spoiled coffee, coffee allergy and other conditions. There is no stimulating factor in coffee, which will not affect the normal peristalsis of gastrointestinal tract and will not cause diarrhea. However, when the patient drinks too cold coffee, which leads to cold stimulation of the intestinal tract, or drinks deteriorated coffee, which leads to the emergence of gastroenteritis, as well as coffee allergy, which leads to the patient’s intestinal mucous membrane edema, all of these will affect the function of intestinal tract, which will lead to the patient’s intestinal excessive peristaltic movement, and thus diarrhea will occur. Coffee does not stimulate the intestinal tract, generally simply drinking normal coffee is not diarrhea, when patients drink coffee diarrhea need to find out the cause of diarrhea as soon as possible, to deal with the cause.