Blood in the stool is the discharge of blood from the anus. Blood in the stool, or all blood in the stool, bright red, dark red or tarry in color, is called blood in the stool. Blood in stool is usually seen in the lower gastrointestinal tract, especially in the colon and rectum, but occasionally it is seen in the upper gastrointestinal tract. The color of blood in the stool depends on the location of the bleeding, the amount of bleeding, and how long the blood stays in the intestine. Causes of blood in stool Almost all GI bleeding can cause blood in stool, but there are two common causes of blood in stool: (a) “False blood in stool”: False blood in stool is caused by eating certain foods and medications that can cause the stool to change color. Such as taking blood iron, carbon powder, bismuth, herbal medicine, or after eating pig liver, animal blood, tomatoes, beets and other foods, the stool can be dark brown, black or red. Sometimes bleeding in the mouth or nasal cavity can also cause a change in stool color after swallowing. These are pseudo-blood in the stool, after stopping the use of drugs and food, “blood stool” will disappear. (B) “real blood in stool”: For real blood in stool refers to blood in stool caused by anorectal diseases, hemorrhoids, anal fissures, rectal polyps, colon polyps, ulcerative colitis and even colon cancer, rectal cancer, etc. will appear the symptoms of bleeding stool, so we should pay attention to. 1, “bright blood-colored blood stool” — benign causes are more common Mostly acute (immediate) bleeding, blood flows out of the blood vessels outside for a short time through the anus with fecal discharge, or directly after the stool. The appearance of the blood that comes out resembles traumatic bleeding and is bright red or purplish red or dark red in color, and can coagulate into a blood clot after a little time. (1) Hemorrhoids: External and mixed hemorrhoids can cause bleeding in the stool in all periods, usually with fresh blood in the stool or dripping blood after the stool. External hemorrhoids usually do not bleed in the stool. (2) Intestinal polyps: painless fecal bleeding. The amount of bleeding varies. Generally, the blood does not mix with the stool, or the polyps may mix with the stool if they are in a high position and in large quantity. (3) Rectal prolapse: anal swelling repeatedly prolapses, and bleeding during defecation may occur after prolonged illness. (4) Anal fissure: bleeding in the form of blood attached to one side of the fecal surface, not mixed with feces, and dripping blood after stool in some patients. 2. “Stool with pus and blood and mucus” – beware of intestinal cancer! That is, there is both pus (mucus) and blood in the excreted stool. Pus (mucus) blood stool is often seen in the rectum or colon tumors and inflammatory diseases. The following diseases are common: (1) rectal cancer: the blood is fresh or dark red, there may be mucus in the stool, and often blood, mucus and stool are mixed together, which may be accompanied by discomfort such as thinning of the stool, abnormal increase in the number of stools, and the feeling of incomplete defecation. (2) Colon cancer: the first symptom can be manifested as bleeding in stool (especially tumors in the left hemicolectomy), mostly bloody stool with pus or mucus, dark blood color, which can be accompanied by abdominal mass, abdominal pain, chronic progressive wasting and other symptoms. (3) Ulcerative colitis: longer history, recurrent episodes of mucus stools or pus-blood stools, accompanied by left lower abdominal pain or lower abdominal pain. (4) intestinal infectious diseases: such as bacterial dysentery, amoebic enteropathy, etc. 3, oily black shiny stool – is your stomach okay? Also known as tarry stools, black or brownish-black stools. One of the most common symptoms of upper gastrointestinal bleeding: such as gastric ulcers, duodenal bulb ulcers, etc. If the amount of bleeding is small, and the bleeding rate is slow, the blood stays in the intestine for a long time, the discharged stool is black; if the amount of bleeding is large, the stay time in the intestine is short, the discharged blood is dark red; the bleeding is particularly large, and can also be bright red when discharged quickly. 4, the naked eye can not see the blood stool – the latent blood stool is more terrible! A small amount (trace) of gastrointestinal bleeding will not cause a change in stool color, only positive in the fecal occult blood test, called occult blood stool. Occult stools can occur in all diseases that cause GI bleeding, commonly ulcers, inflammation, and tumors. The stool occult blood test detects a small (trace) amount of blood in the stool. Regular stool occult blood testing is an important way to screen for colorectal tumors. The harm of blood in stool: Blood in stool can easily make the body lose a large amount of iron and cause iron deficiency anemia. In general, the development is slow and there can be no symptoms or mild symptoms in the early stage, but when the anemia is heavy, pale face, tiredness, loss of appetite, palpitation, accelerated heart rate and shortness of breath after physical activity, swelling, etc. Some patients may even have neurological symptoms such as agitation, excitement, irritability, etc. At the same time, blood in stool is also an early sign of intestinal malignant tumor. Since the situation of blood in stool is similar to that of bleeding hemorrhoids, it is difficult for people to distinguish it, and some people do not pay enough attention to it, which makes early malignant tumor easily ignored and leads to tragedy. What should I do if I have blood in stool? People generally believe that bleeding stools are caused by hemorrhoids, which is incorrect. The main symptom of hemorrhoids, especially the first and second stage internal hemorrhoids, is blood in the stool. Blood in the stool usually occurs during defecation, dripping or jet-like bleeding during and after the stool, and the blood does not mix with the stool, and repeated bleeding can lead to severe anemia. The diagnosis of hemorrhoids is relatively easy, but it must be noted here that anorectal diseases with symptoms of blood in the stool, such as rectal adenoma and colorectal cancer, are often misdiagnosed as internal hemorrhoids in clinical practice, so other intestinal or even systemic diseases must be excluded when determining the diagnosis of hemorrhoids. In addition to asking the patient’s medical history and performing routine physical examination, it is necessary to perform a detailed specialist physical examination on the patient: for example, anal finger examination by a specialist, disposable anoscopy, disposable trocar proctoscopy, etc. These examinations are convenient, economical, safe and accurate. In addition, for patients who have a family history of inflammatory bowel disease (IBD), intestinal tumor, or a long history of disease and other risk factors, clinicians often recommend patients to perform e-colonoscopy or abdominal CT for examination and diagnosis.