3 causes of black stool are gastrointestinal disease, eating certain foods such as blueberries, blood sausage or black licorice and taking medications such as iron pills, or Pepto Bismol or other medicines containing bismuth.
Black stool or black poop can also be caused by dehydration.
Stool or poop that appears blackish or reddish in color can be a concern.
It can indicate that you have blood in the stool and may be a more serious gastrointestinal tract issue.
However poop or stool that simply seems darker than normal may be the result of dehydration, constipation, or eating dark-colored foods or iron-rich foods or supplements.
The most common causes of black stool or black poop include.
Iron Supplements.
Dark-Colored Foods.
Medicines With Bismuth.
Bleeding Ulcer.
Esophageal and Gastric Cancers.
Mallory-Weiss Tear.
Esophageal Varices.
Liver problems can also cause black stool or black poop.
In the later stages of cirrhosis, you may vomit blood or have tarry, black stools.
This is because blood can't flow through the liver properly, which causes an increase in blood pressure in the vein that carries blood from the gut to the liver (portal vein).
Melena is also another cause of black stool or black poop.
If your black stool looks tarry or sticky and has a strong smell, it might be melena.
Melena means you're bleeding somewhere inside.
Internal bleeding is always serious, especially when you can't tell if it's stopped.
The blood that turns your stool black has traveled some distance.