1. Hemorrhoids. It is not difficult to distinguish between hemorrhoids and rectal cancer, and misdiagnosis is often caused by failure to conduct serious examination. Hemorrhoids are usually painless blood in the stool, and the blood is bright red and does not mix with the stool, while rectal cancer blood in the stool is often accompanied by mucus and appears as mucus blood stool and rectal irritation symptoms. Patients with blood in stool must routinely perform rectal examination. 2.Anal fistula. Anal fistula is often caused by paranal abscess formed by anal sinusitis. Patients with a history of paranal abscess, local redness and pain, and rectal cancer symptoms are more obvious differences, the identification is relatively easy. 3. Amoebic enteritis. The symptoms are abdominal pain and diarrhea, and the lesion involving the rectum may be accompanied by shortness of breath. The stool is dark red or purplish blood and mucus. Enteritis can lead to granulation and fibrous tissue proliferation, thickening of the intestinal wall, narrowing of the intestinal lumen, easily misdiagnosed as rectal cancer, fiber colonoscopy and biopsy as an effective means of differentiation. 4, rectal polyps. The main symptom is blood in the stool, fiberoptic colonoscopy and biopsy as an effective means of differentiation.