Blood in Dog Stool: Why Is There Blood in My Dog’s Poop?

If you’re the kind of person who freaks out at the sight of any blood in your dog’s poop, your dog is better off than if the opposite were true. Blood has no business being in the poop.

It is not always the end of the world type of emergency, but it always needs to be taken seriously.

Blood in Dog Stool: Why Is There Blood in My Dog's Poop?

How quickly you need to see a vet depends on how much blood there is, and whether there is also diarrhea, vomiting lethargy or other concerning signs.

One drop of blood does not an emergency make, but things can change quickly.

If the blood in your dog’s stool looks like actual blood, it is coming from the large intestine, rectum, or nearby structures. If it came from higher up in the gastrointestinal tract, it would not have the typical bright red appearance. Such partially-digested blood would make the stool look dark and tarry.

Dietary indiscretions

A dietary indiscretion, particularly with diarrhea, can irritate the colon enough to cause mucus and even blood in the stool. Even an abrupt change of food can do that to some dogs. JD did this to himself on occasion; his poop would be runny with the odd drop of blood. He’d act normally otherwise, and the problem would resolve itself by the next day. He did not need veterinary treatment.

Jasmine would have a small amount of blood in her diarrhea when her IBD was acting up. She did need medical attention. Just goes to show that the same signs in different dogs can mean very different things.

GI injuries

A foreign body, such as a piece of a stick, a chunk of undigested bone, rocks, and other objects can injure the lining of the gastrointestinal tract and make it bleed. Again, the injury can be minor or major; are you willing to take a wild guess?

One question I always keep in my mind, how much blood there might be that I don’t see? Is my dog in pain? Lethargic? Bleeding anywhere else? Having unexplained bruising? Looking swollen?

Hemorrhagic gastroenteritis (HGE)

They recently changed the name of this condition to acute Hemorrhagic Diarrhea Syndrome (AHDS) because it seems that the stomach actually isn’t involved with the problem.

Whatever they choose to call it, it doesn’t make it any less terrible. Either way, it comes with lots and lots of blood. It’s what I meant when I said that a couple of drops of blood don’t an emergency make, but this can change in a blink of an eye.

With HGE/AHDS the poop can look like straight blood. Clearly, that is an extreme emergency. That’s also while I said that it is better to be paranoid and see a vet with one drop than wait until things might get this bad.

Bloody diarrhea characteristic of acute hemorrhagic diarrhea syndrome. Photo CriticalCareDVM


If a puppy has any amount of blood in the poop, it’s an emergency. In fact, a sick puppy is always an emergency no matter the signs. Bloody diarrhea is a common symptom of the dreaded disease parvovirus but can also be seen with a variety of other viral and bacterial diseases that can affect puppies and adult dogs.


The parasites most likely to cause blood in the stool are hookworms, whipworms, Coccidia and Giardia. Sometimes symptoms like diarrhea and a pot-bellied appearance appear first but blood in the stool may be the first indication that a dog has intestinal parasites. Either way, intestinal parasites can kill a dog, particularly a puppy, so never think “oh, it’s probably just worms.”

Another thing that can cause bloody diarrhea is stress.

Stress can not only aggravate any existing problem, such as IBD but even cause what is called stress colitis with bloody diarrhea with mucus.

There are other causes

Inflammation of an anal sac, blood clotting problems, twists or other problems within the gastrointestinal tract, perianal fistulae, polyps, and even cancer can all cause blood in/on the stool.

If you’re an experienced dog parent, you might be able to tell when a few drops of blood are not a big deal and when you should see a vet as soon as possible. Even then I always tend to err on the side of caution. I’d recommend to at least talk to your veterinarian if you find blood in your dog’s poop.

Related articles:
What’s in the Poop?

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Jana Rade edited by Dr. Joanna Paul BSc BVSc

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. Dr. Joanna Paul BSc BVSc is our wonderful sponsor and has been kind to edit and fact-check my important articles.

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