When there is a lot of prolonged bleeding from the anus, that is, when there is a lot of bleeding from the anus for a long period of time with blood in the stool, anal diseases, rectal diseases, colon diseases or amoebic dysentery should be considered. It is recommended to go to the hospital for diagnosis and treatment as soon as possible. 1. Anal diseases include anal fissure, internal, external and mixed hemorrhoids and anal fistula. Most of the anal diseases cause bleeding and pain in the anus, while anal fistula may even be accompanied by pus. 2. Rectal diseases include rectal polyps and rectal cancer. Rectal polyps are common in children, usually in small amounts and intermittent. Rectal cancer is mainly manifested by increased frequency of bowel movement, thinning of stools, sometimes with blood and mucus, accompanied by acute and severe pain, and in advanced stage, there is often foul smell in stools and substantial weight loss, which need to be highly valued. 3. Colon diseases include colon polyps, colon cancer, chronic non-specific ulcerative colitis and bacillary dysentery. Colon polyps are mainly manifested by blood in the stool, often accompanied by malnutrition, anemia, hypoproteinemia and so on. Colorectal cancer is common in the left half of the colon, which is characterized by persistent constipation and increased frequency of bowel movement, and pus and blood can be discharged when the cancerous tumor breaks down. 4. Amoebic dysentery: it is an infectious disease caused by protozoa, mainly parasitized in intestines, with stools of soy red color, much mucus and foul smell. Prolonged bleeding from the anus involves a lot of diseases with this phenomenon, so you need to go to the hospital as soon as possible to do the relevant examination, differential diagnosis, to give a reasonable standardized treatment, to avoid delays in the condition, resulting in adverse consequences.