Pooping blood without pain is most commonly caused by hemorrhoids, which are swollen veins in the rectum or anus that can bleed without causing pain. Other possible causes include anal fissures (small tears in the skin around the anus which might bleed with little to no pain), colon polyps, or more serious conditions like inflammatory bowel disease or colorectal cancer, though these typically require medical evaluation. If the bleeding is bright red and not accompanied by pain, hemorrhoids are the likely cause. However, blood in stool should never be ignored, especially if it persists, even if there is no pain, as it may signal other underlying conditions that require treatment. It is important to consult a healthcare professional to diagnose the cause and get appropriate care, especially if there are other symptoms like changes in bowel habits, prolonged bleeding, or if the bleeding is dark or mixed with stool.