Bright red blood in stool can be caused by colon cancer, rectal polyps, hemorrhoids and other diseases, which should be taken seriously and timely consultation. 1. Colon cancer: it refers to malignant tumors occurring in the colon, preferably in cecum, transverse colon, sigmoid colon, ascending colon and descending colon. At present, the cause of the disease is not clear, but genetic factors, previous history of colon lesions, obesity, smoking and other people are more likely to suffer from colon cancer. The main manifestations are blood in feces, abdominal pain, abdominal mass, constipation and other symptoms. 2. Rectal polyp: it refers to the proliferation of rectal mucosal surface protruding into the intestinal lumen, which is a common clinical anorectal disease. At present, the cause of the disease is not completely clear, but the age, obesity, smoking, heredity and other high-risk factors. The main manifestations of blood in the stool, abdominal pain, diarrhea, increased frequency of stool and other symptoms. 3. Hemorrhoids: a common disease, due to the varicose veins of the anal canal, when defecation, fecal injury to the varicose hemorrhoidal veins, which can lead to symptoms of bleeding in the stool, usually no pain symptoms. Bleeding in the stool is also seen in other causes, it is recommended to go to the regular hospital in a timely manner to find out the cause of the disease, and actively cooperate with the doctor to carry out regular treatment and medication, so as not to delay the condition.