Bleeding before defecation during bowel movement may be related to bleeding internal hemorrhoids, anal fissure, colonic and rectal malignant tumors. 1. Internal hemorrhoidal bleeding: can be due to long-term dry stool, squatting or alcoholism, poor diet and other reasons, stimulation damage to the mucosa of internal hemorrhoids, so that the internal hemorrhoidal vascular mass local breakage caused. It can be manifested as the symptom of bleeding in the stool first and then defecation, usually in bright red color, mostly painless blood in stool. There may also be anal swelling, anal itching and other symptoms. 2. Anal fissure: It is a tear or rupture of the skin of the anal canal, which can be caused by infection, long-term constipation and trauma. Patients will have typical symptoms such as pain and blood in stool, so it can also cause bleeding in stool first and then defecation. And the anal pain usually worsens after defecation. 3. Malignant tumor of colon and rectum: when stool passes through the cancerous tumor, it can rub the surface of cancerous tumor and cause blood vessel rupture, which leads to blood in stool. Therefore, the phenomenon of bleeding before defecation can also occur. If liver metastasis occurs in the advanced stage of cancer, which affects the coagulation function, it will aggravate the situation of blood in stool. In conclusion, if there is bleeding before defecation, it is recommended to go to the hospital in time to avoid delaying the condition and eat more fresh fruits and vegetables in daily life.