What causes black or red stools / poo?
I am guessing that either you or someone you know has noticed they have either black or red coloured stools / poo, and as a result you have decided to check out the Internet in order to find out why this is happening, what the cause might be, and if it is something to worry about. Possibly you or your friend may have noticed blood in their stools / poo, which usually causes immediate panic and a fear of all kinds of terrible conditions. You may also have found this article as a result of reading my very popular original article called Have you examined your stools / poo lately?
Most individuals find it very uncomfortable to discuss the colour and nature of their stools or poo with anyone, even close family. They find it embarrassing to talk to their Doctors about these things because it just seems a little bit too gross, especially if you have been a patient of the same Doctor for many years on a less 'intimate' basis. This is why so many people resort to the Internet, looking for quick, easy to find answers to their concerns, hoping they can make lifestyle changes to resolve their odd coloured stools, as opposed to finding out they may potentially have a serious problem.
This particular article will cover the possible reasons for black or red stools / poo, but if you want to look into other colours of stools or poo, and find out the causes of these, there is a list at the bottom of this article along with links to those articles.
The Causes of Black Stools / Poo
As I state in all my articles on the reasons for stools to be unusual colours, there are many reasons why your stools / poo may change colour. The same applies to black or red stools, and this is a list of the many reasons that your bowel movements may begin to appear to be black or red, possibly have blood in them, be tarry or sticky in nature and generally not as you would expect a normal stool to be.
Black stools caused by blood:
Black sticky / tarry, foul smelling stools can be caused by the presence of blood in the stool / poo. This is known as melena or melaena and is diagnosed if more than 200ml of blood is found in the stool when a fecal occult blood test is performed. The fact the blood is dark in colour indicates it is 'old' blood, and therefore originated early in the gastrointestinal tract giving enough time for the bacteria/digestive enzymes in the colon to break down the blood into chemicals . This can indicate the following:
- A bleeding ulcer in either the esophagus, stomach or the small intestine
- Vascular Malformation, abnormal blood vessels
- Some kind of trauma or the presence of a foreign body
- Widened and enlarged veins called varices in the esophagus and stomach
- A Mallory-Weiss tear, the esophagus has been torn through severe vomiting
- Bowel Ischemia, a lack of normal blood flow to the intestines
- Gastritis, an inflamed lining to the stomach
Black stools in general can be caused by:
- Eating black liquorice
- Taking iron supplements
- Taking Pepto Bismol or Kaopectate. This is caused by the active ingredient they contain called bismuth subsalicylate.The dark coloured stools or poo may last for several days, but should return to a normal colour once you stop taking the bismuth subsalicylate
- Eating lots of green leafy vegetables such as spinach, broccoli etc
- Eating blueberries or other dark coloured foods
- Drinking Guinness or red wine
The Causes of Red Stools / Poo
The medical term for a red stool caused by the presence of blood is hematochezia. The fact that the stool / poo is a brighter red in colour can indicate the source of the blood was lower in the gastrointestinal tract. The presence of red blood in the stool can be caused by the following:
Red stools caused by blood:
- Anal Fissures. These are small tears or ulcers in the sides of the anus usually caused by straining when constipated, giving birth or ulcerated hemorrhoids
- Colon Polyps. Small growths on the sides of the colon that are thought to be a sign of future colon Cancer.
- Crohn's Disease and Ulcerative Colitis are collectively known as Inflammatory Bowel Disease (IBD). Unfortunately these disorders are not curable but aspects of the conditions can be treated surgically
- Internal Hemorrhoids (piles). These are essentially veins in the rectum and anal area. When these become swollen you may experience itching and discomfort, pain and tender external lumps in the anal area. Frequently you will find blood on the toilet tissue when you wipe and may experience a stinging sensation when straining. Creams are available to ease the problem and you can also help them by reducing your caffeine and alcohol intake, and increasing your dietary fibre and water intake
- Diverticulosis. This is when pouches called Diverticula form in weakened areas of the colon (large intestine). If these Diverticulum become irritated and infected the condition is called Diverticulitis. The two conditions together are called diverticular disease
- Colon Cancer (Bowel Cancer) can be indicated by dark red or bright red blood mixed in with your stools / poo.
- Some kind of trauma or a foreign body
- A small bowel tumour
- Vascular Malformation, abnormal blood vessels
- Intestinal infection e.g. bacterial enterocolitis
- Irritable Bowel Syndrome (IBS).
Red stools in general (False hematochezia) can be caused by:
- Ingesting red foods such as beetroot, tomatoes, Kool-Aid, red gelatine, hot cheetos and popsicles
- Certain chemicals within the body
- Various metabolic actions can cause the imbalances of certain proteins and other chemicals to be removed as waste products by the body. These are expelled in your stools / poo causing them to take on the color of the metabolized substances
Disclaimer: Please remember this article is intended only as a guideline. If you are concerned about the fact your stools / poo appear to have become black or red in colour, then I would urge you make an appointment with your Doctor quickly so that you can get a professional medical diagnosis without relying on the Internet as a reliable source of information.
Other Unusual Coloured Stools / Poo articles by mistyhorizon2003
- What causes yellow stools / poo?
If you are reading this then it is probably because you want to know what causes your stools / poo to turn yellow. There are a number of reasons this can happen, and this article aims to provide you with a list of possible reasons for your yellow sto
- What causes pale coloured stools / poo?
Are you concerned that your stools or poo have suddenly changed from a healthy brown colour, to a pale, grey or beige colour? If you are and you want to know what could be causing these change in colour, you need to read this article and find out why
- What causes orange stools / poo?
If you have noticed that your stools / poo have suddenly begun to come out orange, and you are wondering what the possible causes of this might be, then this is the article for you. It covers a number of causes for your bowel motions to be orange in
- What causes green stools / poo?
So you want to know why your stools / poo have turned green, but you are not quite ready to face the embarrassment of going to a Doctor to have this investigated further. This article will give you a break down of many of the possible causes of green
More by this Author
If you have noticed that your stools / poo have suddenly begun to come out orange, and you are wondering what the possible causes of this might be, then this is the article for you. It covers a number of causes for your...
Are you concerned that your stools or poo have suddenly changed from a healthy brown colour, to a pale, grey or beige colour? If you are and you want to know what could be causing these change in colour, you need to...
Have you examined your stools / poo lately? Perhaps you should. This article explains what you might see in the toilet, and what it might mean.