Blood in stool, also known as rectal bleeding, is a symptom that may indicate bleeding somewhere in the digestive tract, ranging from the rectum to the stomach. The appearance can vary from bright red blood on the surface of the stool or toilet paper to dark, tarry stools that suggest bleeding higher in the gastrointestinal tract. Common causes include hemorrhoids, anal fissures, inflammatory bowel disease, infections, diverticulosis, or colorectal polyps, though more serious conditions such as colorectal cancer must also be considered. Additional symptoms may include abdominal pain, changes in bowel habits, weakness, or unexplained weight loss. Because the underlying cause can range from minor to serious, any persistent or unexplained blood in the stool should be evaluated by a healthcare professional.