Why is there blood in my stool? What does it mean?
Medically reviewed by Carmen Fookes, BPharm. Last updated on Sep 9, 2019.
If you find blood in your stool, or if your stool looks red, it is important not to ignore it, as it may be a sign of a serious condition. If you can’t find a dietary reason for the color change (see below), talk with your doctor as soon as you can.
Take note of:
- How much blood there is. Try and estimate the quantity, for example, one teaspoonful or is it more a constant drip. Do you have to wear protection in your underwear (such as incontinence pads) to stop it getting on your clothes?
- What color is it? This can help identify the cause. For example, bright red or maroon blood is usually a sign of hemorrhoids or an anal fissure (a small tear in your anus). Dark, tarry, blood may indicate bleeding in the upper digestive tract.
- When do you notice it? Is it just on the toilet paper when you wipe after a bowel motion, is it mixed in with the stool, or is it just sitting on top?
- Do you have any other symptoms, such as bleeding or bruising elsewhere, constipation, fatigue, pain, or weight loss?
Red Stool Causes
Conditions that can make the stools look red or bloody include:
- Anal fissures
- Bleeding in the lower part of the digestive system
- Crohn’s disease
- Ulcerative colitis.
Black Stool Causes
Conditions that cause the stools to look black (which may signal old blood or bleeding higher up in the digestive system) include:
- Bleeding within the GI tract (eg, from stomach ulcers)
- Bowel ischemia (a reduction of blood flow to the intestines)
- Vascular malformations (misshapen veins in the intestines).
Dietary Reasons For Red Stools
Some foods or medicines may also make your stools look red. Examples include:
- Tomato juice/soup
- Red drink mixes
- Red gelatin
- Red food coloring
- Sun-dried tomatoes
- Worming medications.
Some foods or medicines may also make your stools look black. Examples include:
- Bismuth subsalicylate (Kaopectate, Pepto-Bismol)
- Dark chocolate
- Iron supplements
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