Blood in the stool is considered to be a relatively common symptom of anorectal diseases, constipation patients are often found in the stool with fresh blood or blood dripping from the anus after the panic, do not know the specific symptoms, indiscriminate use of medication, afraid to come to the doctor, so that the condition is delayed. Today I will give you an introduction to the relevant anal and intestinal diseases, caused by constipation with fresh blood of the common diseases are mainly the following: 1, hemorrhoid bleeding Hemorrhoid patients, due to anal pain during defecation, often inhibit the desire to stool, and gradually produce constipation, constipation is aggravated to a certain extent hemorrhoids. When the hemorrhoid nucleus is large, hemorrhoidal mucosal tissue becomes thin, when straining to defecate dry fecal matter is easy to rub through the hemorrhoidal mucosa, causing blood in the stool. It is characterized by forceful defecation, blood discharged from the anus, blood is often attached to the surface of the stool, there can be anal drip blood after defecation, or hand paper stained with blood. 2.Bleeding colon diverticulum Colon diverticulum is the colon wall protrudes outward to form a pouch. It can be single, but more often is a series of sac-like protrusions from the intestinal lumen outward. Manifested as sudden heavy bleeding, bright red color with blood clots. 3.Isolated rectal ulcer bleeding, also known as benign isolated rectal ulcer, benign nonspecific rectal ulcer, is due to benign isolated acute and chronic ulcers of the anterior wall of the rectum caused by gastrointestinal disorders, abdominal pain, constipation, diarrhea, pus and blood in the stool as the main manifestations of the majority of the symptoms for the surface of the stool with blood accompanied by pain in the anus area. 4, anal fissure bleeding constipation caused by anal fissure, constipation further aggravated, in the force of defecation, dry feces expansion of the anal canal, can make the anal canal small blood vessels tear and bleeding, which is characterized by a small amount of bleeding, or feces surface with blood, or defecation of blood dripping out, or after the handkerchief stained with blood. Another characteristic is that patients with anal fissure often have severe tear-like anal pain. Therefore, when there is periodic severe anal pain caused by defecation with blood in the stool, anal fissure should be considered. 5, colorectal polyps, especially rectal polyps bleeding, most people although the intestinal mucosa polyp formation, but no conscious symptoms, because the small polyps are only in the intestinal mucosa with elevated nodules. Large polyps are often small tumors with tips, protruding into the intestinal lumen, can move up and down in the intestines, due to fecal pressure and irritation, the surface is often ulcerated, erosion, and even bleeding. Bright red blood can be seen on the surface of feces, or mixed with feces, or mixed with mucus and pus secretion. Rectal polyps often manifest as painless blood in stool, usually with small amount of bleeding. When there are larger polyps in colon, it can cause intussusception, lower abdominal cramps, aggravation of constipation, and blood in feces. Colorectal cancer includes rectal cancer, sigmoid colon cancer and colon cancer, whose main symptom is blood in feces. If the cancer is located in the right half of colon, such as ileocecal part, ascending colon, hepatic flexure part of colon, it is usually not easy to see obvious bleeding, and the positive fecal occult blood is the main symptom; if the cancer is located in the left half of colon, the color of blood in the stool is bright red or dark red, attached to the surface of feces, and if there is not much bleeding, but due to constipation and retained in the intestinal lumen for a long period of time, then the blood color is blackened, and blood and feces are mixed together. Sigmoid colon cancer often manifests as constipation alternating with diarrhea, with blood, pus and mucus in stool; rectal cancer is blood in stool or pus and blood stool, or mucus and blood stool with bloody secretion in stool. In short, stool with fresh blood indicates that the bleeding site is in the digestive tract below the large intestine, especially the sigmoid colon, rectum and anus in the left half of the colon. Blood in the stool is an important symptom that should not be ignored and should be treated promptly.