Black Stool - Should I Be Worried?

Black stool ! You notice this when you go to the bathroom; should you worry? Is this a medical emergency or just something you have eaten? You are probably wondering " what does black stool mean ?" Find out here when you should take action and what the possible causes are.

Melena is the medical term used by your doctor to describe this type of stool when it is caused by bleeding from high up in the intestinal tract.

False melena is dark stool caused by something else.

In this section of the website we are going to look at different stool types and when you should be concerned. We are starting with black stool. This can have different causes but if it is dark black and has a sticky, tarry, loose consistency and is like diarrhea it will probably indicate that you are bleeding from somewhere in the intestinal tract.

Normally the bleeding site will be in the esophagus (the food pipe), the stomach or the duodenum (the first part of the small intestine attached to the stomach).

As the stools pass along the intestinal tract enzymes start to digest the blood and it turns from red to black.

Sometimes bleeding from lower down in the intestines can cause melena if the transit time of the stools is very slow.

If you experience this type of bowel movement you should see a doctor urgently. Sometimes melena can indicate a slow bleed but if it is severe or you have more than one episode it could indicate a large hemorrhage, especially if you feel faint and have a rapid heartbeat. If this happens to you, then go to the hospital immediately.

Melena Case Study

Black Stool Causes

There are many different things that can cause black stool. Some of them need further investigation as they are causing bleeding but this color stool can be the result of ingesting certain foods and medications. In these cases it is nothing to worry about.

Causes of Bleeding That Can Lead to Black Stools

• Bleeding ulcer in the stomach or the duodenum
  
• Tear in the esophagus due to major vomiting (Mallory-Weiss tear)
• Widened veins of the stomach or esophagus (varices)
• Inflammation of the stomach or esophagus
• Crohn’s Disease
• Overdose of blood thinning drugs like Coumadin (Warfarin)
• Use of certain medicines like aspirin, steroids and chemotherapy drugs
  
• Tumors of the upper intestinal tract
• Foreign body causing trauma
• Trauma caused externally via a blow for example
• Bleeding from an abnormal blood vessel
  

False Melena

There are some things which when ingested can lead to black stool but this type of false or pseudo melena is not caused by dangerous bleeding and is not usually anything to worry about.

If you have black feces when you open your bowels, before you begin to panic, first consider, could it be one of these things which can make a person's stool change to this color?

Are My Stools Really Black?

Sometimes it can be difficult to tell if you have black stools or if they are dark green because in the toilet bowl these two colors can look very similar.

A good way to tell the difference is to open your bowels onto some tissue and smear some onto white paper. Shine a light onto the paper and you will easily be able to tell if you have black stool or dark green.

For more information about green stools see here.

Complications

Black stools or melena can lead to hypovolemic shock. This is when the volume of blood in the circulation falls by one fifth or more. It is a medical emergency and if not treated promptly can lead to death. The symptoms are:

• Cool clammy skin
• Pale skin
• Rapid breathing
• Rapid weak pulse
• Feeling faint or dizzy
• Weakness
• Little or no urine output
• Confusion and or agitation
• Unconsciousness

If you suspect shock then lie the affected person flat, keep them warm and raise their feet (unless they have a spinal or head injury). Give nothing by mouth. Seek emergency medical help immediately.

If you go to the bathroom and are shocked to see black stool do not panic. First think about anything you have eaten or swallowed which may have resulted in black stools. If however, you have tell tale black tarry stools which are like the tar that they use to repair the roads you should immediately seek medical attention.

If you have other types of diarrhea then please look at causes of diarrhea.

For more information about black poop and different types of stool please see the related pages below.

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