Always after lunch diarrhea at night is fine, may be caused by physiological factors, but also does not rule out pathological factors such as gastroenteritis, irritable bowel syndrome and other causes. 1. Physiological factors: If you eat at noon more greasy, spicy and other stimulating foods such as fat, chili, etc., may stimulate the gastrointestinal mucosa, so that the normal digestive function is affected, gastrointestinal peristalsis to speed up the gastrointestinal tract, there may always be after lunch diarrhea at night all right situation. If it is not accompanied by other discomforts, it is generally a normal physiological phenomenon. 2. Gastroenteritis: generally due to the patient’s long-term bad eating habits, such as overeating and other causes, inflammation repeatedly stimulate the gastrointestinal mucosa, which can easily lead to abnormal digestive function, food in the stomach for a shorter period of time, easy to produce diarrhea symptoms. If you eat irritating food when eating lunch, it is easy to make the situation worse, thus appearing always eat lunch after diarrhea at night is fine. 3. Irritable bowel syndrome: belonging to the functional intestinal lesions, patients with common symptoms of abdominal pain, bowel changes, abdominal distension, etc., lesions attacked due to the lunch at the time of eating stimulating food, easy to make the vagus nerve reflex enhancement, resulting in gastrointestinal reflex activity enhancement, increase intestinal peristalsis, so that always eat lunch diarrhea at night, all right situation. If the patient always after lunch diarrhea at night is fine, if by adjusting the diet, the symptoms failed to improve, it is recommended to consult a doctor in a timely manner, under the guidance of the doctor, improve the relevant examination, to clarify the cause of the disease, symptomatic treatment.