The reason for the bleeding during the defecation is many: 1, if the blood in the stool is bright red, the possible cause is mixed hemorrhoids, especially internal hemorrhoids, usually when the abdominal pressure increases or constipation, which can easily lead to pathological hypertrophy of the anal cushion, downward movement, prolapse out of the anus and the formation of the hemorrhoid nucleus stagnation swelling, hemorrhoid vein stasis and thus the formation of bleeding. The bleeding is usually spotted or sprayed, and is controlled after the stool stops.2, bleeding during defecation is also a common cause of anal fissure, with the increase in pressure of defecation, the trauma of anal fissure will ooze some blood, and the surface of the stool will be bloody when wiped, usually bright red, with painful symptoms.3, bleeding during defecation may also be rectal polyps and rectal adenoma, long-term stool stimulation is likely to make the mucosa The long term stimulation of the stool will easily cause the rupture of the blood vessels under the mucosa, resulting in blood in the stool, which is usually bright red. Therefore, there are many reasons for bleeding during defecation, and rectal examination should be performed, and if necessary, anoscopy should be inserted to clarify the diagnosis.