Dog Vomiting Blood but Acting Normal: Top Reasons and Solutions

This article was updated on May 1st, 2023

A dog who vomits blood is enough to set off alarm bells in your head. Sure, dogs vomit all the time. They get into the garbage, eat something in the park, or feel side effects from new medications. For the most part, throwing up every now and again is a normal – if somewhat unpleasant – experience.

But it can be terrifying to see a dog vomiting up drops of red blood! Right away, panic sets in.

“Oh my gosh,” your mind starts to race frantically. “Are they dying? Did they swallow something sharp, like glass? Is it a cut in their mouth? An internal bleed? What?”.

And yet your dog seems to be acting like nothing happens – everything else seems to be going great.

Today on Senior Tail Waggers, let’s look at the top reasons why a dog might be vomiting blood, plus practical solutions that will help you decide when it’s time to seek veterinary attention. Vomiting blood can range from acute and mild to chronic and life-threatening, and it’s key that dog owners know the difference.  

4 Top Causes of Dogs Vomiting Blood – But Otherwise Acting Normal

To start, the medical term for vomiting blood is “hematemesis.” It could appear in several ways. For example, vomit might contain streaks, clots, or flakes of blood. Color might be bright and runny or dark, brown, and thick.

This blood in a dog’s vomit may come from their digestive tract. For instance, a problem in the stomach, esophagus, or small intestines. A dog who is acting normally could also have a small bleed somewhere in their mouth.

If your dog has never vomited blood before, you will need to do some detective work to figure out why it’s happening now.

The following are the top 4 causes of a dog vomiting blood (but still acting normal).

1. Injury to the digestive tract, mouth, nose, or respiratory tract

Dogs can injure themselves in small ways, and their owners are none the wiser. After all, unlike people, canines cannot speak! They aren’t able tell us what’s wrong using words. A slice from a sharp stick or antler chew across the gums, tongue, and walls of the mouth could be the reason your dog seems fine, but vomits blood.

Similarly, a traumatic bump to the nose (or a broken tooth) could lead to blood being swallowed. Later, this gets thrown up.  

2. Stomach ulcers

Next, your dog could have a stomach ulcer. Symptoms include lack of appetite, abdominal pain, high heart rate, lethargy, bloody stools, and of course, vomiting blood. But here’s the thing – these signs are easily missed. You might assume your dog is simply a little tired. Or being fussy about their food. Not to mention, there is really no way for a pet owner at home to measure heart rate. Bloody stools from ulcers often look black rather than bright red, like you would expect blood to look. That’s because blood turns black once it goes through the digestive system.

So, if a dog is otherwise acting totally ordinary, it then becomes challenging to diagnose why they are vomiting blood. Stomach ulcers could very well be the reason. Only a veterinarian will be able to diagnose with certainty.

3. Cancer

Third on the list of reasons why a dog might vomit blood but be acting normal is cancer. Like stomach ulcers, cancer can take time to detect. Tumors that grow in the stomach and throat will be fleshy masses. These lumps are internal and may not cause any other signs until they reach a larger size. That means owners aren’t able to feel or see them on a dog’s skin.

Bleeding is a common symptom. However, it might not show up for 3+ months. Dogs can behave normally, until the cancer starts affecting their bodies more aggressively.  

4. Toxin Ingestion

Lastly, your happy-go-lucky pooch might vomit blood if they eat something toxic. Chemicals (like rat poison) are formulated to kill rodents. If accidentally ingested by a dog, chemicals can cause internal bleeding. Surprisingly, a dog may act normal for several hours to days before the effects of the poison become obvious…leaving fur parents completely unaware that anything is wrong!

Until their dog starts vomiting blood, that is.

If you suspect your pup has ingested a toxic substance, call your local animal poison hotline immediately and go to an emergency veterinarian ASAP. For a thorough list of other common causes, please read Why is There Blood In Your Dog’s Vomit?

Vomiting Blood but Acting Normal: Is it a Vet Emergency?

From minor health issues to serious medical conditions, there are lots of reasons why a dog might vomit up blood.

The question is, “If my dog is still playing, eating, drinking, etc. do I need to treat bloody vomit as an emergency situation?”

The answer is…yes!

No matter how little the amount, always consult a trained veterinarian whenever you see spots, drops, or large amounts of blood. Hematemesis isn’t rare. However, it can turn deadly. Perform a quick visual inspection of your dog.

Do you see any of the following?

• White or pale gums instead of pink
• Pain or distress
• Weakness / lethargy
• Difficulty breathing
• Dehydration
• Shock
• Collapse

Don’t forget!

Sudden blood loss is a health risk for any dog. Even if they are going about their ordinary routines and only throwing up blood randomly, this should be treated as a medical emergency, always.

What Will a Veterinarian Do to Help a Dog Who Is Acting Normal, but Vomiting Blood?

Either over the phone or in person, your vet will want to know everything. Be prepared to answer questions in detail. The more you can describe your dog’s state, the quicker your veterinarian will be able to diagnose them. For instance, they will ask about the color, mixture, amount, and frequency of the vomiting.

For dogs who show no noticeable gum/teeth wounds or mouth injuries, your vet will want to run diagnostic tests.

These can include:

• Abdominal ultrasound
• X-rays
• Blood tests including blood clotting (coagulation) tests
• Testing for infectious diseases
• Urine or fecal tests

Naturally, all of this can add up cost-wise. Medical care for dogs who vomit blood – even if they seem normal otherwise – can still run into hundreds or thousands of dollars. Talk to your vet about options, and remember to call your pet insurance company.

Hopefully, it’s nothing too serious. A dog can be prescribed medication for pain relief and to protect the gut from future vomiting episodes. In serious cases, blood transfusions or surgery might be required. To hasten recovery, your veterinarian may instruct your dog to follow a strict diet. Small meals made up of highly digestible and low-fat dog foods will help any dog suffering from bloody vomit.

Final Thoughts

And there you have it!

A concise explanation of what to do when your dog is acting normal but vomiting blood. Though Senior Tail Waggers acknowledges this can be a downright scary situation, the good news is that hematemesis is treatable, so long as it’s caught early.

For more educational content from our expert vets, visit: Why is My Dog Vomiting Blood and What Should I Do? [Vet Advice]