Tummy pain and diarrhea, which is also known as abdominal pain accompanied by diarrhea, is mostly caused by acute gastroenteritis, but can also be caused by gastrointestinal malignant tumors, food poisoning and other factors. 1. Acute gastroenteritis: patients often have a history of dietary impurity, in the abdominal pain, diarrhea at the same time, there is often a fever, nausea, vomiting and other accompanying symptoms; through the improvement of blood routine, stool routine and culture and other tests can assist in the diagnosis. 2. Food poisoning: food poisoning is caused by eating food contaminated by bacteria, toxins and toxic substances, and patients may also have abdominal pain and diarrhea. If the co-eaters have similar manifestations, the disease should be highly suspected, and the cause of poisoning should be clarified by blood test, stool test, pathology and toxin test. 3. Gastrointestinal tumors: patients with tumors will also have abdominal pain, diarrhea, and accompanied by pus and blood stools, bloody stools, or mucous blood stools and other manifestations, which can be diagnosed or differentiated through gastroenteroscopy. Since the causes of abdominal pain and diarrhea are many and complicated, if the abdominal pain and diarrhea are not relieved for a long time, please consult a doctor in time to further improve the relevant examinations to determine the cause of the disease and treat the symptoms, so as to avoid delaying the disease.