Patients with blood after stool may be caused by perianal diseases and intestinal diseases, as follows: First, perianal diseases: common ones are hemorrhoids and anal fissures, hemorrhoids will manifest as painless, intermittent blood dripping during and after stool, or even jet bleeding, bright red in color, bleeding volume is on the high side, accompanied by hemorrhoid nucleus prolapse. Anal fissure bleeding is low, accompanied by anal pain during defecation and constipation. Secondly, intestinal diseases: it may be caused by intestinal diseases, such as intestinal tumors, intestinal polyps and intestinal inflammatory lesions, and the bleeding is mostly dark red in color, accompanied by changes in stool habits, mucus stools, mucus-purulent stools and other symptoms. Therefore, when patients have blood in the stool, they should pay attention to it and go to the hospital to see an anorectal specialist for relevant examinations to clarify the cause before taking the corresponding treatment to avoid any missed diagnosis.