Blood in stool refers to the discharge of blood from the anus during or after defecation, with blood dripping from the anal opening, blood on the surface of the fecal strip or blood on the hand paper after defecation. The color of blood in stool is bright red, dark red or tar-like, and sometimes blood is mixed with stool and mucus. The color of the blood in the stool depends on the site of the GI bleeding. The upper gastrointestinal tract such as the esophagus, stomach, duodenum, liver, biliary tract, and pancreas bleed mostly in brown or tar-like black stools. In the case of bleeding from the lower GI tract, such as the small intestine, colorectum and anal canal, the stool is mostly dark red or bright red. Blood in the stool is a common symptom of many gastrointestinal disorders, most commonly associated with perianal disorders such as hemorrhoids and anal fissures. The incidence of hemorrhoids in the population is 50% to 70%, so it is said that “nine out of ten people have hemorrhoids”. Hemorrhoids manifest as blood in the stool or blood dripping after the stool, the amount of blood can be more or less, especially the first and second stage internal hemorrhoids with blood as its main symptom. Blood in the stool usually occurs during defecation, in the form of jets, or after the stool dripping blood, blood and feces do not mix. The amount of bleeding varies, usually from a few milliliters to tens of milliliters, and repeated bleeding can lead to severe anemia. However, blood in the stool may also be a sign of intestinal malignancy. Rectal polyps also present as fresh or dark red blood after stool. This disease is considered as precancerous lesion, and polyps should be removed by endoscopic high-frequency electrosurgery or other surgical procedures as early as possible after clear diagnosis. Colorectal cancer is usually found in the left colon and rectum, and its development is closely related to the stimulation of local chronic inflammatory lesions, invasion of carcinogenic substances and polyp malignancy. Clinically, the disease is mostly manifested as mucus and blood stool or dark red blood stool, as well as other symptoms of bowel discomfort such as lower abdominal distension, urgency, increased frequency of bowel movement, deformation of stool and other general symptoms such as emaciation, malnutrition and weight loss. The disease can be diagnosed through anal finger diagnosis, colonoscopy and pathological examination. Early detection, early diagnosis and early treatment are very important to improve the survival quality of colorectal cancer patients. Some colorectal cancer patients do not pay attention to recurrent blood in stool and increased number of bowel movements, and they always think that it is bleeding from hemorrhoids, so they neither go to hospital for consultation nor use medicine for treatment, and the misdiagnosis can last for half a year or even one year. This can delay the disease in the lighter cases and can be life-threatening in the more serious ones. We have found such cases in our clinic from time to time. Therefore, we recommend that “blood in the stool should not be ignored” and that if recurrent blood in the stool occurs, you should be vigilant and seek early medical attention and treatment.