Blood in the feces is usually an abnormal manifestation, mostly considered to be caused by perianal diseases such as hemorrhoids, anal fissure or intestinal diseases such as inflammatory bowel disease, colon cancer and rectal cancer. 1. Perianal diseases: such as hemorrhoids, anal fissure, etc., the mucous membrane and blood vessels in the anal canal of the patient are relatively fragile, and when the stool passes through, it will damage the mucous membrane and blood vessels, causing bleeding and leading to the patient’s feces with blood in it. 2. Gastrointestinal diseases: such as inflammatory bowel disease, colon cancer, rectal cancer, etc., in the active period of the disease, the intestinal mucous membrane may be damaged and bleed, which will be discharged with the stool, causing the patient to have blood in the feces. At this time, patients may be accompanied by abdominal pain and bloating, nausea and vomiting, loss of appetite and other uncomfortable symptoms. If the patient has blood in the feces for a long time or repeatedly, it is recommended to consult a doctor in time to identify the cause of the disease and carry out targeted treatment to avoid delaying the condition.