What’s In the Vomit?

by Jennifer Coates, DVM

Dogs are built to vomit. No, I’m not kidding. 

A part of the brain named the “vomiting center” is especially well developed in dogs, and they have a layer of skeletal muscle throughout the length of the esophagus that essentially allows them to vomit at will.

So, if your dog occasionally throws up but you can point to the reason why (e.g., he ate too much, he ate too quickly, he ate something yucky, you’re driving on a curvy road) and he’s perfectly normal in all other regards, you probably have nothing to worry about.

There are times, however, when vomiting can be indicative of a serious medical problem, which begs the question, “How is an owner supposed to know when to be worried and when to write off vomiting as a dog just being a dog?”

Paying close attention to exactly what a dog is doing and producing will usually reveal the answer.

If your dog exhibits any of the following symptoms, play it safe and call your veterinarian:
  • vomiting more than once or twice in a day
  • projectile vomiting (a sign of possible gastrointestinal obstruction)
  • poor appetite
  • diarrhea
  • lethargy
  • weight loss
  • changes in drinking and urinary habits
  • abdominal pain
  • abdominal enlargement

But that’s not all.

An often overlooked method of determining whether or not a dog’s vomiting is serious is to examine the vomit itself. 

I know, you’re thinking “gross,” but there really might be some good information in there. Here’s what to look for.

1. Nothing – as paradoxical as it may sound, a dog that is trying to vomit but nothing is coming up may be in the greatest danger of all. This is a classic symptom of gastric dilatation and volvulus (GDV or bloat), a life-threatening condition that necessitates immediate veterinary attention if an affected dog is to survive.

2. Bright red blood – if there is more than just the smallest streak of blood, call your veterinarian ASAP. It should go without saying that if a dog is bleeding from his gastrointestinal tract, he needs immediate veterinary attention.

3. Coffee grounds – no your dog didn’t just raid the garbage can, this material is partially digested blood, call your veterinarian ASAP.

4. Worms – yes, dogs can vomit up gastrointestinal parasites. Roundworms are the most likely culprit, particularly in puppies. If your dog has just been dewormed, this is not an immediate cause for concern as long as he is happy, active, eating, drinking, and pooping. Continue with your deworming protocol. If your dog has not been dewormed recently, he needs treatment – call your veterinarian.

5. Frothy yellow or orange-tinged fluid
– the froth is mucus mixed with other gastrointestinal fluids and the yellow-orange pigment comes from bile, which is secreted into the upper part of the small intestine. If your dog tends to vomit up fluid like this when his stomach is empty, he may have a condition known as “bilious vomiting syndrome.” Most cases can be managed by feeding more frequently throughout the day. Offering two or three small meals rather than one big one will usually do the trick.

6. Bright green material – some types of rodenticides (poisons used to kill mice and rats) are died a bright green color. If you notice a green discoloration to your dog’s vomit, call your veterinarian immediately.

And while you’re poking around in the vomit, collect a sample to bring to your dog’s veterinarian should you decide to make an appointment. 

The vet may not need it, but if they do (e.g., to test for a poison) you’ll be happy you didn’t throw it all away.


Jennifer Coates, DVM graduated with honors from the Virginia-Maryland Regional College of Veterinary Medicine in 1999.  In the years since, she has practiced veterinary medicine in Virginia, Wyoming, and Colorado.  She is the author of several books about veterinary medicine and animal care, including the Dictionary of Veterinary Terms: Vet-speak Deciphered for the Non-veterinarian

Dr. Coates has recently joined the PetMD team and she is now writing for the Fully Vetted column; great blog, do check it out.

Jennifer also writes short stories that focus on the strength and importance of the human-animal bond and freelance articles relating to a variety of animal care and veterinary topics.  Dr. Coates lives in Fort Collins, Colorado with her husband, daughter, and pets.

Articles by Dr. Coates:
Kidney Disease – Say What? 
What Happens In The Dog's Body When The Kidneys Fail To Function Properly? 
Heat Stroke: What Happens In The Dog's Body?  
The Perplexities of Pancreatitis
The Other Side Of The Coin: The Cost Of Defensive Medicine
To Neuter Or Not To Neuter… That Is The Question
Don’t Forget the Physical Therapy
Common Misdiagnoses (Part 1)
Common Misdiagnoses (Part 2)
Picking the Right Dog to Breed
When Is It An Emergency?
Dog Allergies: Common, Commonly Misdiagnosed, or Both? 
Why Does The Spleen Get No Respect?
Protect Your Dog From Snake Bites 
More Creepy Crawlies
Why I Dislike Inflammatory Bowel Disease
Salmonella – A Significant Problem, Or Not?

Related articles:
Vomiting in Dogs: Is He Actually Vomiting?
Causes of Vomiting in Dogs
The Story Of Flossy And The Mystery Vomiting
Whats In The Urine? (Part I: What You Can Notice On Your Own)
What's In The Urine? (Part II: Urinalysis)
What's In The Blood? Blood Testing And Interpretation


  1. Hi Jana,

    This is really useful - my Mum is never sure whether she should be worried or not when I'm vomiting….

    Wags to all,

    Your pal Snoopy :)

    1. Hey Snoopy! It's natural to worry. With time, though, once learns when to panic and when not.

      Kind of like with kids. At first the parent freaks out over every little thing; with more time and more kids, things become less horrifying, "oh, you broke a leg? Just slap some splint on it," sort of deal. LOL

  2. Interestingly, I took Sage's vomit to the emergency hospital after she got into marijuana, but they said it wouldn't help.

    I have something sweet for you! Come see: http://wp.me/p10wZH-1jT

    1. I don't imagine it would be helpful with all substances ...

      What is that link? Looks kind of suspicious.


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