What causes rectal bleeding without hemorrhoids?

Blood in the stool without hemorrhoids may be caused by various factors, mainly including: 1. Anal fissure: Long-term constipation, diarrhea, or excessive anal canal pressure can cause tearing of the anal canal skin, resulting in blood in the stool. Fresh blood is often found on the stool or toilet paper used for wiping. 2. Colorectal polyps: Chronic inflammation can cause abnormal proliferation of rectal or colonic mucosa forming polyps, which may lead to blood in the stool when the surface of a polyp becomes damaged. It is usually accompanied by symptoms such as polyp prolapse and mucus in the stool. 3. Inflammatory bowel disease: Conditions such as ulcerative colitis can cause damage to the intestinal mucosa, leading to blood in the stool, possibly accompanied by symptoms like diarrhea and abdominal pain. 4. Malignant intestinal tumors: Such as colon cancer and rectal cancer. Early stages may be asymptomatic, while later stages may present with symptoms including blood in the stool and tenesmus. 5. Other factors: Improper diet (e.g., excessive consumption of spicy or irritating foods, alcohol), gastric or duodenal ulcers, and colitis may also cause blood in the stool.