Abdominal pain with blood in stool is considered from several aspects: first, colitis, due to intestinal inflammation can induce abdominal pain and blood in stool, such patients will also have low-grade fever, diarrhea, mucus and blood in stool and other symptoms. Second, colon polyps, there will be blood in the stool, mucus stool, diarrhea and even abdominal pain, no clinical manifestations, only found during physical examination. Third, perianal abscess, the formation of rectopelvic abscess, will induce pain and discomfort in the lower abdomen, and accompanied by pus and blood in the stool, fever, pain and other discomforts, and the perianal local skin temperature is higher, fluctuating sensation. Fourth, tumors, abdominal or intestinal tumors, induced abdominal pain, and tumor invasion of blood vessels, can also cause pus and blood stool. This kind of patients will be accompanied by changes in defecation habits, changes in stool characteristics, fatigue, emaciation, and should seek early medical care for a clear diagnosis.