When experiencing painless rectal bleeding, it’s first important to consider hemorrhoids as the cause. Hemorrhoid bleeding typically presents as bright red blood, occurring mostly after defecation, and is painless and intermittent. Hemorrhoid bleeding may arise from inappropriate diet or excessive fatigue from staying up late. In contrast, bleeding from rectal cancer tends to be less in volume and often mixes with the stool, accompanied by increased frequency of defecation, mucus in the stool, changes in stool characteristics, or abdominal pain. Clinically, to rule out rectal cancer, it is often recommended that patients undergo a colonoscopy to check for any masses in the intestines. If a mass is present, a biopsy can determine if it's cancerous. Patients with rectal cancer generally exhibit symptoms like weight loss and anemia. Thus, for painless rectal bleeding, hemorrhoids are more generally considered, rather than rectal cancer at first thought.