DON'T PANIC - The Causes of Blood in your Dog's Poop!

If you have found blood in your dog’s stool then it’s easy to panic and think the worst. Thankfully, the most common causes of blood in a dog’s poop are not serious or life-threatening.

Some though will need prompt treatment at the veterinary hospital, while others can be treated successfully at home.

causes of bloody diarrhea

Why does my dog have bloody diarrhea?

And so my first question is from Jem, and she noticed that her dog had some diarrhea with blood that was first discovered in the morning and she's just wondering what the cause is and treatment options are.

Causes of Bloody Diarrhea

  1. Simple colitis

  2. Hemorrhagic gastroenteritis

  3. Intestinal infections

  4. Parasites

  5. Intestinal foreign body/obstruction

  6. Bowel Tumor

  7. Anal gland abscess

Simple colitis

So I'm going to start off with what the causes of diarrhea with blood. Now, a simple colitis is most common, which is an inflammation of the lower intestinal tract. This means not up by the stomach, but lower down in the colon. This is the most common cause of diarrhea with a little bit of blood and by little bit I mean blood flecks, rather than a stool that is completely bloody.

There's very often also some mucous present in the poop and simple colitis also often causes straining. So it might be that your dog is straining to go to the toilet, and seems to want to go potty, but actually very little is being produced. This is a normal sign of colitis as well.

Hemorrhagic gastroenteritis

There are other causes of bloody diarrhea in dogs, with the next one being a condition known as hemorrhagic gastroenteritis. Now this is a disease that, more often than not, comes on very suddenly. It's thought that it's primarily due to a clostridial infection (a certain type of bacteria), although that's not always the case. But you've got a stool or diarrhea that is just incredibly bloody.

So it almost looks like complete blood sometimes, and can cause dogs to become unwell very, very quickly.

They get very dehydrated and they definitely need treatment at the hospital for this.

Intestinal infection

You can also get infections such as parvovirus, which is clearly a very serious infection and one of the main diseases that we vaccinate our dogs against.


We can get bloody diarrhea due to parasites so different types of parasites within the gut including different species of worms and protozoa.

Foreign body

You can have an intestinal foreign body, so a dog who's eaten something and it's working its way down, causing irritation and ulceration of the lower intestines or even getting obstructed. Now by the time it gets down to the lower intestines and when we would expect to be seeing blood, often it will pass because it's already gotten through the most narrow bit of intestine.

If something is getting stuck higher up in the intestine, so in the small intestines or even in the stomach, and if that's causing bleeding, then actually what will happen is we'll see a dark tarry stool. This is because the blood that's being produced and leaking into the intestines is getting digested and that causes a dark black tarry stool.

Bowel tumor

Other causes of bloody diarrhea though can be tumors of the colon so they can be bleeding and tumors can also be interrupting the normal absorption and digestion of the food within the intestines.

Anal gland abscess

And then another thing that can sometimes cause what we think is maybe a bit of blood on the stool is actually a ruptured anal gland abscess. So the anal glands are two sacks that normally express either side of the anus. If they become infected and enlarge than they can burst out through the skin, which can cause quite a bloody, pussy discharge and if that's coating the stool, then you might think that your dog has got bloody diarrhea, but actually they've got an anal gland abscess.

So those are the most common causes of diarrhea with blood in dogs.

How to Treat Bloody Diarrhea in Dogs


What's the treatment then? Well, if we're dealing with a simple colitis, which is like I said earlier, by far and away, the most common thing if a dog is otherwise well, if they're eating, if they're drinking, if there's no vomiting, if they're bright and active then really a bland diet and monitoring a really likely to be sufficient.

I actually discuss in the last episode of the Dr Alex Answers Show all about the different feeding options for a dog with colitis so I’d definitely recommend going back to that episode.

When to seek veterinary treatment

But if your dog has bloody diarrhea and if they're unwell, if there's lots of blood within the stool, so not if it's just a kind of a little bit of a flecking or a small amount of blood but if it's completely covered in blood and there’s blood throughout the stool, then it's definitely best to get checked out by your vet just to check that there's no other treatment. Be that antibiotics, be that intravenous fluids, be that other investigations such as blood tests and x-rays that needs doing.

The above is a transcript taken from “The Dr Alex Answers Show”.

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