The fast-paced life, high-intensity work, and irregular diet are causing more and more people to suffer from anal diseases. Some anorectal diseases have the symptom of bleeding stools, but most people think it is caused by hemorrhoids as soon as they find blood in their stools, but in fact it is not. This situation can easily cause major diseases to be overlooked and not receive timely and effective diagnosis and treatment, causing irreparable trauma to life and health. Therefore, blood in the stool is a symptom that should not be ignored, and it is important to have some understanding of the common diseases regarding this symptom. 1, hemorrhoid bleeding, hemorrhoid patients due to pain in the anus during defecation, often inhibit the desire to stool, gradually produce constipation, constipation and to a certain extent aggravate the hemorrhoids. When the nucleus of the hemorrhoid is larger, the mucosal tissue of the hemorrhoid becomes thinner, and the dry fecal mass easily rubs the mucosa of the hemorrhoid when forceful defecation, causing blood in the stool. It is characterized by forceful defecation, blood from the anus, blood is often attached to the surface of the stool, after the stool can have anal drip blood, or hand paper with blood. 2, anal fissure bleeding, constipation caused by anal fissure, constipation further aggravated, in the force of defecation, dry stool expansion of the anal canal, can make the anal canal small blood vessels tear and bleeding, characterized by a small amount of bleeding, or stool surface with blood, or blood dripping out when defecating, or blood on the hand paper after the stool. Another characteristic is that patients with anal fissures often have severe tearing anal pain. Therefore, when there is periodic severe anal pain caused by defecation with blood in stool, anal fissure should be considered. 3, large intestinal polyps, especially rectal polyps bleeding, most people have polyps formed in the intestinal mucosa, but no conscious symptoms, mainly because small polyps are just raised nodules in the intestinal mucosa. Large polyps are often small tumors with tips that protrude into the intestinal cavity and can move up and down in the intestine. Due to fecal pressure and stimulation, the surface often has ulcers, erosions, and even bleeding. Bright red blood can be seen on the surface of feces, or mixed with feces, or mixed with mucus and purulent secretions. Rectal polyps often manifest as painless blood in stool, generally small amount of bleeding, colon with larger polyps, can cause intussusception, lower abdominal cramps, constipation aggravated, and stool with blood. 4.Colorectal cancer, including rectal cancer, sigmoid colon cancer, colon cancer, whose main symptom is blood in stool. If the cancer is located in the right half of the colon, such as the ileocecal region, ascending colon, colon liver flexure, it is generally not easy to see obvious bleeding, but mainly positive fecal occult blood; if the cancer is located in the left half of the colon, the color of fecal blood is mostly bright red or dark red, attached to the surface of the feces, if the amount of bleeding is not much, due to constipation in the intestinal cavity retention for too long, the blood is dark, blood mixed with feces. Sigmoid colon cancer often manifests as alternating constipation and diarrhea, with fresh blood, pus and mucus in the stool; rectal cancer is blood in the stool or pus-blood stool, or mucus-blood stool with bloody secretions in the stool. In addition to the above diseases, blood in the stool may also be caused by bleeding from a colonic diverticulum or bleeding from an isolated rectal ulcer. The former is characterized by sudden, heavy bleeding, once bright red, and accompanied by blood clots. The latter presents with blood on the surface of the stool and pain in the anal region. In short, fresh blood in the stool indicates that the bleeding site is in the digestive tract below the large intestine, especially in the sigmoid colon, rectum and anus of the left hemithorax. Do not panic when you find blood in the stool, and do not take it lightly when the symptoms are alleviated; blood in the stool is an important symptom that should not be ignored and should be treated promptly.