Is Tarry Stool an Emergency? Melena in Dogs

Your dog’s poop will become black and tarry because of the presence of digested blood.

How does digested blood end up in the poop? When your dog is bleeding in the stomach or small intestine, iron in the blood oxygenates as it moves through the colon, which is what gives it the black color. It might not look as scary as fresh, bright red blood, but it reflects a serious problem.

Is Tarry Stool an Emergency?

When blood doesn’t look like blood

Blood isn’t always the bright red color we expect to see. In the poop, blood looks like blood only when the bleeding is in the large intestine or rectum.

When the bleeding happens higher up in the digestive tract, or blood from the mouth or respiratory tract is swallowed, the digestive processes change what it looks like.

It is still blood.

While finding a bit of fresh blood in the feces may or may not represent an emergency, I’d always consider black, tarry stool to be one unless proven otherwise. It can, sometimes, have a benign reason behind it, but how would one know?

Why is digested blood in the feces scarier then fresh one?

A speck of red blood can quickly get your attention. It takes a substantial amount of blood to change the appearance of the stool to look black and tarry. So you’re not looking at a few drops. Which means a substantial bleed.

That’s why black, tarry stool would scare me way more than a bloody one.

You might be looking at a severe, life-threatening illness. The potential causes of tarry stools in dogs include:

  • bleeding ulcer
  • tumors in the stomach or esophagus
  • severe infection
  • damage from a foreign body
  • abnormal blood clotting
  • poisoning
  • pneumonia
  • kidney failure …

Other symptoms that ought to provide a clue about the seriousness of your dog’s situation depend on where the blood is coming from and can include:

  • vomiting (with or without blood in it)
  • pale gums
  • weakness
  • difficulty breathing
  • coughing up blood
  • bleeding elsewhere
  • and so on

If my dog passed black, tarry stool, I am on my way to a vet.

Related articles:
My Dog’s Poop: What Can You Learn from Your Dog’s Stool

Further reading:
Why Is My Dog Pooping Blood?
Black, Tarry Feces Due to Presence of Blood in Dogs
What Are the Causes of Black Dog Poop?

Categories: Black, tarry stool • Emergencies • Symptoms

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Jana Rade

I am a graphic designer, dog health advocate, writer, and author. Jasmine, the Rottweiler of my life, was the largest female from her litter. We thought we were getting a healthy dog. Getting a puppy from a backyard breeder was our first mistake. Countless veterinary visits without a diagnosis or useful treatment later, I realized that I had to take Jasmine's health care in my own hands. I learned the hard way that merely seeing a vet is not always enough. There is more to finding a good vet than finding the closest clinic down the street. And, sadly, there is more to advocating for your dog's health than visiting a veterinarian. It should be enough, but it often is not. With Jasmine, it took five years to get a diagnosis. Unfortunately, other problems had snowballed for that in the meantime. Jasmine's health challenges became a crash course in understanding dog health issues and how to go about getting a proper diagnosis and treatment. I had to learn, and I had to learn fast. Helping others through my challenges and experience has become my mission and Jasmine's legacy. I now try to help people how to recognize and understand signs of illness in their dogs, how to work with their veterinarian, and when to seek a second opinion. My goal is to save others the steep curve of having to learn things the hard way as I did. That is the mission behind my blog and behind my writing. That is why I wrote Symptoms to Watch for in Your Dog, which has turned out being an award-winning guide to dog owners. What I'm trying to share encompasses 20 years of experience.

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