All Health Topics

Stools with blood

Stools with blood can be caused by many different conditions. If you are experiencing bloody stools or bleeding from a bowel movement, you may need to see a doctor.

Published July 2, 2016
• Reviewed by a UI Health Care Provider
on Sept. 1, 2018

Seek immediate medical attention if you are experiencing fever, excessive weakness, vomiting, or seeing large amounts of blood in your stool. 

What does a bloody stool look like?

  • Red blood mixed with the stool
  • Red blood covering the stool
  • Black or tarry stool
  • Dark blood mixed with the stool

If you stool is red or black, it might not be from blood. Certain foods may cause your stools to look red. These include cranberries, tomatoes, beets, or food that is dyed red. Other foods may cause your stools to look black. These include blueberries, dark leafy vegetables, or black licorice. 

Common causes

Hemorrhoids

Blood vessels near the anus that become swollen, due to increased pressure, can bleed or prolapse. Typically, the amount of bleeding from hemorrhoids is small and may be a few drops that appear on toilet paper after passing a stool. Hemorrhoids can occur inside the anus or under the skin around the outside of the anus. The condition is very common, normally painless, and does not lead to cancer. 

If bothersome enough, hemorrhoids can be removed by your doctor. Your doctor may first treat any underlying causes, such as constipation. 

Anal fissures

Small tears in the lining of the anus, typically from constipation or diarrhea, can cause blood with stools. They are painful during and following bowel movements. If you have anal fissures, take measures to prevent constipation or diarrhea. Over-the-counter fiber supplements can help. Your doctor can prescribe additional options to treat an anal fissure that isn’t healing on its own.

What else could it be?

Your doctor can determine the exact cause of stools with blood. Underlying disorders and complications of this condition can be serious. If you’re concerned, always err on the safe side and see a doctor.

Pay attention to what the blood in your stool looks like. 

  • How much blood is there? 
  • How often does it occur? 
  • What color is the blood? 

This will help your doctor zero in on the problem. 

Blood in stools can come from any area of the gastrointestinal tract. 

This includes 

  • Esophagus 
  • Stomach 
  • Small intestine 
  • Large intestine 
  • Rectum 

If the blood is red it typically means it came from the lower digestive tract or rectum. If the blood is darker or black, it typically means it came from the upper digestive tract. Whether or not the blood is mixed with the stools or covering it, can also help determine where it came from and what is causing it. 

Additional causes of stools with blood include

Your doctor will need to do an evaluation to determine if any of these conditions are the underlying cause. 

Tests to find the cause

If you are experiencing stools with blood, your doctor may perform one or more of these tests.

  • Colonoscopy- A small device with a camera is inserted in your colon to look for abnormalities.
  • Upper endoscopy-A small device with a camera is used to look inside the upper digestive tract.
  • Stool culture- A sample of your stools is taken to look for abnormalities.
  • Blood test- A sample of your blood is tested for a number of different potential issues.
  • Capsule endoscopy- A tiny capsule, with a camera inside, is swallowed to take pictures of your digestive track. 

All causes of bloody stools should be determined and monitored by your doctor.