Blood in stool can have multiple causes, ranging from benign to potentially serious conditions. Common causes include:
- Hemorrhoids: swollen veins in the anal or rectal area which can bleed due to straining or constipation. This is a very common cause of bright red blood in stool.
- Anal fissures: small tears in the skin of the anus caused by passing hard or large stools, often painful and resulting in bright red bleeding.
- Inflammatory bowel diseases (IBD) such as Crohn's disease or ulcerative colitis, which cause inflammation and bleeding in the digestive tract.
- Gastrointestinal infections and ulcers which can cause bleeding farther up the digestive tract; blood may appear darker or black.
- Polyps or cancer in the colon or rectum, which can cause bleeding; though less common, this is a more serious cause.
- Other causes include diverticulitis, medication effects, or trauma in the GI tract.
Blood in stool color and appearance can give clues about the source of bleeding: bright red blood usually means bleeding in the lower digestive tract, dark red or black blood suggests bleeding higher up. If blood is seen in stool, it is important to get a medical evaluation to determine the cause, especially if it is recurrent or accompanied by other symptoms like pain, weight loss, or changes in bowel habits. Even small amounts of blood should not be ignored and warrant a doctor's visit for diagnosis and appropriate management.
If the appearance of blood in stool is sudden and associated with symptoms like dizziness or weakness, urgent medical care is recommended.
