What to Do When Your Dog Vomits Yellow Bile

Bilious vomiting syndrome is usually not serious, but it may be worth taking your pup to the vet to rule out other causes.

Senior dogs commonly experience bilious vomiting syndrome. By: Alexey Matveichev

Yellow bile vomit is something experienced by many middle-aged or older dogs. The scenario is usually that the dog is otherwise well, with a good appetite and normal poop, but she regularly throws up bile, especially when she’s hungry.

This is often a nagging worry, but not serious enough to seek a veterinary consult in its own rite. And if they remember, people mention at their pet’s annual booster checkup.

In the majority of dogs, this is down to a condition known as “bilious vomiting syndrome.” So what is this condition, and is it serious?


Bilious Vomiting Syndrome

The yellow fluid you see your pet vomit is bile. This is processed in the liver, stored in the gall bladder and squirted into the first part of the small intestine (where it joins the exit to the stomach). Bile’s job is to help the digestive process and, once mixed with food, it passes harmlessly down the intestine, where part of it is reabsorbed and recycled back to the liver.

So how does bile that’s supposed to pass down the intestine end up in the opposite direction in the stomach?

It seems likely that slackness in the valve at the exit of the stomach (the pylorus), allows bile to pass in the wrong direction. This is quite common, but normally stomach contractions milk the bile back into the safety of the small intestine.

In bilious vomiting syndrome, when the stomach is inactive, those contractions are weaker or don’t happen. Bile (also known as bile acids) is an irritant, so when it sits in contact with the stomach wall, this causes mild inflammation and irritation.

Hence, the dog with an empty stomach overnight may vomit up bile in the morning.

Changing up your dog’s diet may help reduce symptoms of bilious vomiting syndrome. By: Lukasz Hejnak

Seriousness of the Syndrome

Happily, not in the vast majority of cases. I liken it to suffering from mild morning sickness. The dog feels nauseous and throws up, then is ready to eat and get on with his day.

However, it tends to happen in middle-aged or older dogs, which is also an age group at greater risk of other problems. This means your vet may check out more serious possibilities, just to be on the safe side.


The sorts of problems she’ll want to rule out include:

  • A stomach ulcer
  • Inflammatory bowel disease
  • Giardia infection
  • Stomach cancer or intestinal lymphoma
  • A foreign body in the digestive tract

To do this can mean blood tests, imaging the gut using ultrasound or endoscopy, and fecal analysis.

Helping Your Dog

For straightforward cases where more serious problems have been ruled out, the answer is often a simple change in feeding pattern.

For example, if your dog eats once or twice a day, then switching to several small meals could be the answer. This keeps the stomach active and working away for longer, so there’s less chance of bile sitting in the stomach.

At the very least, it can be helpful to give a carbohydrate-rich meal (such as boiled rice or pasta) an hour or 2 before bedtime. Not only does this provide something slow to digest for the stomach to work away on, but also the carbohydrate does a great job of mopping up bile.

If your dog has gastritis (inflammation of the stomach lining) due to long-term exposure to bile, then this change in feeding pattern may take a while for your dog’s body to get used to. Indeed, occasionally, some dogs need a little extra help in the form of medication.

This guardian cooks up some plain chicken and rice for his sick dog:

When Diet Change Doesn’t Work

If the problem continues, and the vet hasn’t already ruled out other health problems, then now is a good time to do so. When these tests come back clear, the next step is to add in medication.

These medicines will coat the stomach lining and protect it, or reduce the amount of acid in the stomach. (And before you reach for a human indigestion medication, know that some contain ingredients, such as aspirin, that can be dangerous to dogs. Never medicate a pet with human medicines without first checking with your vet.)

Alternatively, the vet may prescribe a “prokinetic,” which is a drug that encourages the stomach muscles to contract.

Happily, bilious vomiting syndrome is rarely serious and responds to simple changes. So if your senior is a little sick each morning, he has my permission to have an extra biscuit at bedtime. Nom nom nom.


This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed March 10, 2017.


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