The main consideration is internal hemorrhoids, rectal polyps, rectal cancer, etc. You should consult a doctor in time to find out the cause of the problem. 1. Internal hemorrhoids: blood in the stool is the main symptom of internal hemorrhoids, which can lead to bleeding when defecating, and some of them will show up as dripping blood after defecation, or appear as jet-like bleeding. The blood color is bright red without clots, and there is no pain or itching during defecation. 2. Rectal polyps: Rectal polyps can cause different degrees of blood in the stool. The amount of bleeding is usually small, and the blood is reddish in color and adheres to the surface of the stool, sometimes there are grooves in the stool. If there is more bleeding, it can be fresh blood or blood clots, or it can be shown as blood dripping from the stool, but no pain will be felt during defecation. 3. Rectal cancer: Rectal cancer is a kind of malignant tumor disease with high morbidity, early clinical manifestation is not obvious, some people will have blood in stool, and there is no pain and itching sensation when they have blood in stool, which is often manifested as mucus-pus-blood stool. Painless bleeding in one bowel movement may also be caused by anal fistula, coagulation dysfunction disease and other diseases. You should go to the hospital in time, complete the examination, clear diagnosis and follow the doctor’s instructions to avoid delay.