The reason for diarrhea after eating is considered to be intestinal infection, functional dyspepsia, irritable bowel syndrome and other causes. 1. Intestinal infection: If there are bacteria or viruses in the food, it is easy to cause local inflammatory reactions such as congestion and edema of the gastrointestinal mucosa, resulting in gastrointestinal dysfunction, decreased digestive capacity, abdominal pain, diarrhea, nausea and other symptoms. 2. Functional dyspepsia: Increased sensitivity of the digestive tract, excessive gastric acid, Helicobacter pylori infection, excessive mental and psychological stress, etc., can cause gastrointestinal dysfunction, but there is no organic lesion. There may be epigastric discomfort, fullness after eating, diarrhea, abdominal pain, nausea and other manifestations. 3. Irritable bowel syndrome:It is a functional intestinal disease, mainly characterized by abdominal pain, bloating, diarrhea, constipation and other symptoms, which may be accompanied by fatigue, urinary frequency and other symptoms. The course of the disease is long and the symptoms are recurrent, but the prognosis is generally good. It can be induced or aggravated by gastroenteritis, food intolerance, chronic stress, surgery and other factors. There are many other causes of diarrhea after eating, such as getting cold. It is recommended to consult a doctor in time for a clear diagnosis and targeted treatment.