Frequent stomach pain and diarrhea may be caused by irritable bowel syndrome, ulcerative colitis, rectal polyps, bowel cancer and other factors. 1. Irritable bowel syndrome: it may be related to psychological factors, food factors, etc., which may make the patient often have the symptom of stomach pain, and may be accompanied by the performance of diarrhea or constipation. 2. Ulcerative colitis: may be related to environmental factors, autoimmune, infection and other factors, acute patients may have obvious abdominal pain, diarrhea symptoms, may also be accompanied by nausea, fever and other manifestations. 3. Rectal polyps: when there are polyps in the intestines, most of the patients do not have obvious performance, but some of the patients will have abdominal pain, diarrhea and other discomforts, and there may be a small amount of blood in the stool, and there may be a rectal polyp prolapsing out of the anus during the bowel movement. 4. Bowel cancer: it may be related to environmental factors, hereditary factors and dietary factors, which may cause patients to suffer from frequent abdominal pain, and may have the symptoms of constipation and diarrhea alternately, and in the late stage, there are often weight loss and anemia. Frequent stomach pain and also diarrhea indicate the existence of abnormalities, and it is recommended to seek timely medical examination and treatment to avoid aggravation of the lesions.