My Dog Has Blood in His Poop: What Should I Do?

It can be quite concerning to discover that your dog has blood in their poop. Today, our Boulder and Westminster vets explain some possible causes, as well as what you should do if you notice blood in your pup's stool. 

Help, There's Blood in My Dog's Poop!

Noticing blood in your dog's stool is bound to worry any pet owner, and can be a sign of a serious health problem.

Whenever you see blood in your pet's stool, it's a good idea to call your regular vet. It can be difficult to determine whether or not this constitutes an emergency.

Our vets explain some scenarios in which your dog needs a trip to the vet, and when you should seek emergency vet care for your pet.


If you have a young puppy with blood in their stool, visit your vet immediately! Parvovirus is common in unvaccinated pups and can be fatal if not treated quickly. Call your regular vet within normal office hours, or visit emergency care for after-hours services.

Assess Your Dog's Overall Health 

Seems Normal

If your dog has blood in their stool but otherwise seems happy (eating and behaving normally), it's a good idea to call your regular vet to seek their advice. Your regular vet will be able to assess the urgency of the situation and let you know whether it's a good idea to bring your pet into the office for an examination.

Seems Unwell

If you've noticed blood in your dog's stool and your dog also vomiting, refusing to eat, and looking unwell, it's time for an immediate trip to the vet. During normal business hours contact your regular vet and book an emergency appointment, after hours you should call your emergency vet.

Assess Your Dog's Stool

Take a moment to examine your dog's stool before heading to the vet. Your vet will be able to diagnose your dog's condition more quickly if you can provide an accurate description of your dog's stool. When it comes to blood in your dog's stool, there are two distinct types:


This blood has been digested or swallowed, typically indicating a problem in the upper digestive tract. Melena results in a black inky stool that can be jelly-like in consistency. Diarrhea is not common with melena, the stool is usually formed. 

Common causes of melena include stomach inflammation, stomach ulcers, and cancer.


Hematochezia is bright red blood or fresh-looking blood in dog stool that stems from the lower digestive tract or colon. Hematochezia may appear on a firm formed stool or in diarrhea. The distinctive bright red color of hematochezia indicates that the blood comes from the lower part of the digestive tract and has only traveled a short distance through the dog's body. 

Common causes of hematochezia include viral diarrheas, colitis, inflammatory bowel disease, and cancer.

Possible Causes of Blood in Stool

It's important to note that a red stool may not indicate blood at all. If your dog has eaten a red nonfood item such as a crayon or lipstick, they could pass a red stool. Red icing and cakes may also have this effect on your dog's stool,

Streaks of bright red blood in your dog's stool could be caused by an infection or injury to your dog's sensitive rectal area, such as a ruptured anal sac. 

Other causes of blood in stool include:

  • Parvovirus
  • Inflammatory bowel disease
  • Severe food intolerance
  • Viral and bacterial infections 
  • Hemorrhagic gastroenteritis (HG)
  • Cancer

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

Have you noticed blood in your dog's stool? Call your vet right away. For after-hours or emergency care, contact our Boulder and Westminster vets immediately.