The following symptoms persist for two weeks or more, you should go to the hospital to recommend colonoscopy: 1, change in bowel habits: recently often diarrhea or constipation; compared with the previous, stool shape change or thin; 2, mucus and blood stool: stool often with bright red or dark red blood and mucus; 3, urgent and heavy feeling: always feel that the stool is not finished, but defecation but can not defecate; 4, persistent abdominal pain; pain site is mostly in the middle and lower abdomen, the degree of pain varies. Lower abdomen, with varying degrees of severity, mostly vague or distending pain; 5. Anemia is often accompanied by fatigue and unexplained sudden weight loss.