The causes of bleeding before bowel movement are complex, usually due to hemorrhoids, anal fissure or rectal cancer, etc., and need to be analyzed specifically. 1. Hemorrhoids: Bleeding before bowel movement may be caused by hemorrhoids due to sedentary lifestyle or long-term constipation, which is caused by excessive force during bowel movement. 2. Anal fissure: bleeding before bowel movement may also be caused by anal fissure, in which the patient exerts too much force during bowel movement, resulting in perianal tearing and thus causing blood before bowel movement. 3. Rectal cancer: Bleeding before bowel movement may also be caused by rectal cancer, when the patient defecates, the front end of the stool cuts through the protruding tumor, resulting in bleeding before bowel movement. Bleeding before bowel movement may also be caused by other reasons. It is recommended that once patients find themselves with similar symptoms, they should consult doctors in time to improve relevant examinations and standardize treatment.