Blood in stools is when blood is discharged from the anus and the stools are bright red, dark red or tarry (black) in color. Blood in stool is just a symptom, not a disease. Strictly speaking, bleeding from any part of the digestive tract can cause blood in stool, such as the oral cavity, biliary tract, gastrointestinal tract and anus. However, blood in stool is mostly seen in lower gastrointestinal bleeding, such as colon, rectum and anal lesions. So what kind of disease may we have once we have blood in stool? Below we recognize the meaning of this danger signal from the different characteristics and accompanying symptoms of blood in stool. Fresh blood in stool Fresh blood in stool is mostly acute hemorrhage, and the blood is discharged with feces through the anus within a short period of time after it flows out of the blood vessels, or it flows out directly after the stool is discharged. The appearance of the blood is similar to bleeding from trauma, and it can solidify into blood clots after a short period of time. (1)Internal hemorrhoids All stages of internal hemorrhoids can cause bright red blood during or after defecation, usually feces or stool paper stained with fresh blood, serious blood can appear after defecation, blood dripping, spraying, painless, intermittent or recurrent episodes. (2) Rectal polyps are painless blood in the stool, which is common in children. Bleeding during defecation, stop after the end of defecation, the amount varies, usually blood does not mix with feces. The blood is not mixed with feces. Low rectal polyps can be prolapsed out of the anus after defecation. (3) Anal fissure Bleeding mode for the surface of the feces on one side with blood, not mixed with feces, or only the paper stained with blood, bleeding more patients can have blood dripping after the stool. Its obvious characteristic is that it is accompanied by tearing or cutting pain in the anus during and after the stool, and the pain can last for several minutes or hours after the stool. (4)External hemorrhoids Generally not easy to bleed, inflammatory external hemorrhoids or thrombosed external hemorrhoids rupture can appear anal bleeding, not related to defecation, there is a swelling at the anus, pain, the surface can be seen skin ulcers. (5)Cancer of anal canal Fresh blood during defecation, hard lump in anus, may be painless in early stage, and may be painful in late stage. (6) Anal trauma or foreign body in the anus If accidental sharp object pierces into the anus or swallowing fish splinter, date kernel, shell or other foreign body stuck in the anus, it may cause pain and blood in stool, and there may be pus and blood if infected. 2. Pus and blood or mucus and blood stool, that is, there are both pus (mucus) and blood in the discharged feces. Pus (mucus) and blood means that the feces are mixed with mucus, pus and blood. The following diseases are common: (1) Rectal cancer: Blood is fresh or dark red, and there may be mucus in the feces. Often, blood, mucus and feces are present at the same time, and they stick to each other, but are not completely mixed. It may be accompanied by change of stool shape and bowel habit and obvious rectal irritation, increased frequency of bowel movement, urgency and heaviness. (2)Colorectal cancer: Bleeding in stools occurs gradually with the prolongation of the disease, mostly bloody stools containing pus or mucus, dark color of blood, which can be mixed with feces. (3)Non-specific inflammatory bowel disease, such as ulcerative colitis, often with mucus stool or pus and blood stool at the onset, feces mixed completely with mucus, pus and blood, accompanied by left lower abdominal pain or lower abdominal pain, and may have bowel movement several times to dozens of times a day. (4) Perianal abscess rupture There is often pus and blood flowing from the anus or parianal ulcers, which is not related to defecation, and may be accompanied by obvious pain and fever and other symptoms. (5) Intestinal infectious diseases may have mucus, pus and blood stools, accompanied by obvious urgency, fever and malaise, such as bacillary dysentery, amoebic enteropathy, etc., through the feces to find the pathogens to make a clear diagnosis. 3.Black stool, also known as tarry stool, stool is black or brownish black. It is one of the most common symptoms of upper gastrointestinal bleeding. Bleeding from the esophagus, stomach, duodenum and biliary tract is common. 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 feces is black; if the amount of bleeding is large, and stays in the intestine for a short period of time, the discharged blood is dark red or purplish-red; the amount of bleeding is particularly large, and is often accompanied by vomiting blood. In addition, black stools can also be seen in the consumption of animal blood products, liver or taking certain drugs such as iron, bismuth and carbon. 4, occult blood A small amount or trace of gastrointestinal bleeding will not cause stool color changes, only in the fecal occult blood test is positive, known as occult blood stool. All diseases that cause gastrointestinal bleeding can cause occult blood in the stool, and ulcers, inflammation and tumors are common. The fecal occult blood test detects small or trace amounts of blood in the stool. Early fecal occult blood of intestinal polyps (cancer) can be positive, regular fecal occult blood test is an important way of colorectal tumor screening. 5.Blood in stool accompanied by bleeding from skin, mucous membrane or other organs is mostly seen in hematologic diseases and other systemic diseases, such as leukemia, hemophilia, disseminated intravascular coagulation and so on. So if you find yourself blood in stool, you must pay attention to it, even if it is a benign disease, long-term blood in stool will cause anemia, which will cause serious damage to various organs of the body, and even affect the work, study and life, and if it is a malignant disease, it will threaten the life, so once the body sends out the danger signals of blood in stool, please go to the relevant departments in time for medical treatment, so as not to make mistakes in medical condition and regret for the rest of your life.