Blood in Dog Vomit: Why Is There Blood in My Dog’s Puke?
In general, when my dog throws up once, I don’t panic. Vomiting is a mechanism of purging things the stomach is not happy with. With most dogs, their stomachs get plenty of reason to complain.
Profuse or consistent vomiting, though, is a problem in itself. If there is blood in your dog’s vomit, it absolutely is a problem.

Blood belongs into blood vessels, nowhere else.
When talking about blood in the vomit, what you normally picture is finding what looks like blood–bright red specks, streaks, or clots in the vomit.
That is what it looks like when the bleeding is in the top part of the gastrointestinal tract, usually the esophagus or the mouth (and sometimes from the nose or lungs if it has been swallowed). Partially digested blood, such as from the stomach and further down, doesn’t look like blood at all—it is often brown or black. Your dog’s vomit would then look like it had coffee grounds in it. While that might look much less impressive, it can actually be the scarier scenario of the two.
The appearance of the vomited blood depends on where it came from and how long it remained in the GI system.
Similar to fresh blood in the stool, it can be the result of direct damage to the lining tissues whether from irritation, inflammation, or injury. Profuse vomiting itself can do enough damage to cause bleeding.
Some of the direct reasons for fresh blood in vomit include trauma, ulcers, foreign objects or severe enough inflammation. Makes sense, right? If that wasn’t bad enough, anything that messes with blood clotting or the ability of the body to keep blood where it belongs can do it as well.
Other potential causes include metabolic issues, infections, liver failure, kidney disease, parasites, toxins, cancer, and others. It is also possible that for any blood you do see there can be bleeding you don’t see.
For me, blood in the vomit, whether fresh or digested, is a reason to see a vet right away. Even without any other obvious symptoms in the mix.
A problem serious enough to cause blood in vomit is a problem serious enough to require medical attention.
Even with everything else aside, severe blood loss in itself can be life-threatening. And then there is the reason why this is happening.
Before you figure that you might just wait and see, let me ask you this – would you know that your dog hasn’t eaten rat poison, hasn’t swallowed something sharp that is now poking holes in his tissues, doesn’t have liver failure, isn’t bleeding internally all over the place, or is safe from any other potential disaster that can lead to blood in vomit?
Throw in other potential signs such as lethargy, pain, severe diarrhea, pale gums and you absolutely have a dire emergency on your hands.
Further reading:
Vomiting of Blood in Dogs (Hematemesis)