Always having diarrhea in the middle of the night can be caused by a cold abdomen, indigestion, acute gastroenteritis and other factors. 1. Cold abdomen: not pay attention to keep the abdomen warm when sleeping at night, the abdomen is cold to cause intestinal peristalsis to accelerate and lead to diarrhea always in the middle of the night, accompanied by abdominal pain. 2. Indigestion: Eating too much food can easily cause indigestion. Food that is not fully digested is discharged into the intestines to stimulate intestinal peristalsis, causing diarrhea in the middle of the night. 3. Acute gastroenteritis: acute gastroenteritis is an acute inflammatory disease of the gastrointestinal mucosa. Overeating or unclean eating can trigger acute gastroenteritis, which leads to diarrhea in the middle of the night, which may be accompanied by abdominal pain, vomiting and other symptoms. If the symptoms of diarrhea in the middle of the night occur frequently, the patient should go to the hospital in time to check the fecal routine, colonoscopy and other items, to identify the cause of the disease, and take targeted treatment under the guidance of professional doctors.