Blood in the stool is blood discharged from the anus. Stools with blood, or all bloody stools, bright red, dark red or tarry in color, are called blood in the stool. Blood in stool is usually seen in lower gastrointestinal bleeding, especially bleeding from the colon and rectum, but occasionally upper gastrointestinal bleeding is seen. The color of the blood in the stool depends on the location of the GI bleeding, the amount of bleeding, and the amount of time the blood stays in the intestines. Almost all gastrointestinal bleeding can cause blood in the stool, but there are two common causes of blood in the stool: (a) “False blood in the stool”: False blood in the stool is due to the discoloration of the stool caused by eating certain foods and medications. Such as taking blood iron, carbon powder, bismuth, Chinese herbs, or eat pig liver, animal blood, tomatoes, beets and other foods, stools can be dark brown, black or red. Sometimes bleeding from the mouth or nasal cavity after swallowing can also cause a change in stool color. These are false blood in stools, after stopping the use of drugs and food, “bloody stools” will disappear. (ii) “Real blood in stool”: For real blood in stool refers to the blood in stool caused by anal and intestinal diseases, hemorrhoids, anal fissure, rectal polyps, colon polyps, ulcerative colitis and even colon cancer, rectal cancer and so on will appear the symptoms of bleeding in the stool, so we should pay attention to it. 1.”Blood color bloody stool”— benign etiology is more common Mostly acute (immediate) bleeding, the blood flows out of the blood vessels outside a short time through the anus with the fecal discharge, or directly after the stool out. The appearance of the blood is similar to that of traumatic bleeding, with a bright red or purplish or dark red color, which can coagulate into a blood clot after a short period of time. (1) hemorrhoids: external hemorrhoids and mixed hemorrhoids in all periods can cause bleeding in the stool, usually with fresh blood in the stool or blood dripping after the stool. External hemorrhoids usually do not have bleeding in the stool. (2) Intestinal polyps: painless bleeding in the stool. Bleeding during defecation stops at the end of defecation, and the amount varies. Generally, the blood is not mixed with the feces, or the polyps are high in position and large in number, and may be mixed with the feces. (3) Rectal prolapse: repeated prolapse of anal swelling, bleeding during defecation may be present after prolonged illness. (4) Anal fissure: the bleeding mode is blood attached to one side of the fecal surface, not mixed with feces, and some patients have blood dripping after defecation. (2) “Stool with pus, blood and mucus” — beware of intestinal cancer, i.e., there is both pus (mucus) and blood in the discharged feces. Pus (mucus) blood stool is often seen in the rectum or colon tumors and inflammation. The following diseases are common: (1) Rectal cancer: blood is fresh or dark red, mucus can be found in feces, and often blood, mucus and feces are mixed together, which can be accompanied by discomfort such as thinning of stool, abnormal increase of stool frequency and feeling of incomplete bowel movement. (2) Colon cancer: the first symptom may manifest as bleeding in stool (especially for tumors in the left half of colon), which is mostly pus or mucus blood stool with dark color, and may be accompanied by symptoms such as abdominal mass, abdominal pain, and chronic progressive emaciation. (3) Ulcerative colitis: a long history of recurrent episodes of mucus or pus-blood stools, accompanied by left lower abdominal pain or lower abdominal pain. (4) Intestinal infectious diseases: such as bacillary dysentery, amoebic enteropathy, etc.. 3, oily black shiny stool — your stomach is okay Also known as tarry stool, stool is black or brownish black. One of the most common symptoms of upper gastrointestinal bleeding: gastric ulcers, duodenal bulb ulcers and so on. If the amount of bleeding is small, and the bleeding speed is slow, the blood in the intestine stays longer, the discharged feces is black; if the amount of bleeding is more, in the intestine stays for a shorter period of time, the discharged blood is dark red; the amount of bleeding is particularly large, and when discharged very quickly, it can also be bright red. 4, the naked eye can not see the blood — latent blood more terrible small amount (trace) of gastrointestinal bleeding will not cause stool color changes, only in the fecal occult blood test was positive, known as occult blood stool. Occult blood can occur in all diseases that cause GI bleeding, including ulcers, inflammation and tumors. The fecal occult blood test detects small amounts (traces) of blood in the stool. Early fecal occult blood can be positive for intestinal polyps (cancer). Regular fecal occult blood test is an important way to screen for colorectal tumors (primary screening). Harms of blood in stool: Blood in stool can easily make the body lose a lot of iron, causing iron deficiency anemia. Generally, it develops slowly, there can be no symptoms or mild symptoms in the early stage, and when the anemia is more serious, there will be pale face, tiredness and fatigue, loss of appetite, palpitation, accelerated heart rate and shortness of breath after physical activities, swelling, etc. Some patients may even have neurological symptoms such as agitation, excitement and irritability. At the same time, blood in stool is also an early signal of intestinal malignant tumors, due to the blood in stool and hemorrhoidal bleeding similar to the general public is difficult to distinguish, coupled with some people do not pay enough attention to early malignant tumors can easily be easily ignored and lead to tragedy. Third, what should I do if I have blood in stool? People generally believe that bleeding in the stool is caused by hemorrhoids, which is incorrect. Hemorrhoids, especially the first and second stage of internal hemorrhoids to blood as the main symptom. Blood in the stool usually occurs during defecation, blood dripping or jet-like bleeding during and after defecation, blood and feces do not mix, repeated bleeding can lead to severe anemia. The diagnosis of hemorrhoids is relatively easy, but it must be pointed out here is that in the clinic, anorectal diseases with symptoms of blood in the stool, such as rectal adenoma and colorectal cancer are often misdiagnosed as internal hemorrhoids, so when determining the diagnosis of hemorrhoids, it is necessary to exclude other intestinal and even systemic diseases. For patients with blood in stool, in addition to asking the patient’s medical history and conducting routine physical examination, it is very necessary for the patient to undergo a detailed specialized physical examination: for example, anal fingerprinting, disposable anoscopy, disposable trocar proctoscopy and so on conducted by specialists, the above mentioned examinations are convenient, economical, safe and accurate, and in addition, for the previous inflammatory bowel disease (IBD), intestinal tumors, a family history, In addition, for patients with previous inflammatory bowel disease (IBD), a family history of intestinal tumors, or a long history of the disease and other risk factors, clinicians often recommend patients to undergo electronic colonoscopy, or abdominal CT for examination and diagnosis.