The causes of stomach pain, vomiting and diarrhea include food poisoning, acute gastroenteritis and pancreatitis. 1. Food poisoning: when patients eat toxic substances, such as puffer fish, mushrooms, drugs, etc., the toxic substances are decomposed and will strongly stimulate the mucous membrane of the stomach, esophagus, pharynx and throat, which will cause the mucous membrane to contract violently, and abdominal pain, diarrhea, vomiting and other symptoms will appear. 2. Acute gastroenteritis: patients suffering from this disease experience the above symptoms due to the body’s gastrointestinal mucosa, nerve endings are suddenly and violently stimulated, the secretion of a large number of inflammatory mediators, resulting in increased diarrhea, nausea, vomiting, abdominal pain and other discomforts. 3. Pancreatitis: When inflammation occurs in the pancreas, pancreatic enzymes digest pancreatic tissues, causing pancreatic cells and tissues to degenerate and become necrotic. The necrotic pancreatic tissue stimulates the peritoneal blood vessels and nerve endings, producing abdominal pain; at the same time, it will stimulate the gastrointestinal tissues, leading to contraction, peristalsis, nausea and vomiting, diarrhea and so on. There are many other causes of stomach pain vomiting and diarrhea, when suffering from stomach pain vomiting and diarrhea symptoms, do not blindly take oral medication, to the hospital in a timely manner to clarify the cause of the disease, to avoid delays in the condition.