Health & Care
A beagle or hound dog looking sick and under the weather.
Share this image

Why is My Dog Throwing Up White Foam?

Is your dog throwing up white foam? Some causes include infectious disease, eating strange things, and going too long between meals...

Melvin Peña  |  May 29th 2017


Is your dog throwing up white foam? Bearing witness to this excretory display can be disconcerting at the best of times and cause dog owners to panic at the worst. There are so many reasons for digestive upset in dogs, and they share so many similar symptoms, that general upset can be difficult for veterinarians to diagnose quickly. While some of the causes for foamy, viscous puking — such as a dog finding rotting food in the garbage or ingesting a foreign object — can occur to any dog at any time, the riskiest and most dangerous can either be managed, treated, or prevented.

A dog who gets sick once before returning to normal is likely to have eaten something she shouldn’t. If a dog throws up several times in a day or for more than a couple of days in a row, on the other hand, schedule a veterinary appointment. The leading causes for frothy foam to appear in a dog’s vomit include internal injury, infection, and inconsistent eating habits. The major ones we’ll examine here include:

  • Ingesting toxins, poisons, foreign objects
  • Bilious vomiting syndrome
  • Bloat
  • Kennel cough
  • Pancreatitis and other digestive inflammations
  • Parvovirus
  • Rabies
A small dog looking sick.

Has your dog been vomiting white foam? (Photo by Will Keightly on Flickr)

1. Dogs eating strange things

Eating a foreign object can lead to an upset stomach, indigestion, or intestinal blockages, all of which might reasonably cause a dog to retch. With the exception of dog toys, small, loose objects should be kept well out of the reach of indoor dogs. Toxins for home use — especially chemical cleaners and pesticides directed toward insects or rodents — can also cause adverse reactions. All household chemicals should be stored in tightly-capped, shatterproof containers and never left out after use. If you put out rat, roach, or mouse traps, ensure that they, too, are deployed in spots where your dog cannot be tempted by curiosity. Here is a list of plants and food that can be toxic to dogs. Note the presence of any of these in your home. It may be of critical importance to a veterinarian if a dog is vomiting white foam.

2. Bilious vomiting syndrome

Bilious Vomiting Syndrome in dogs is similar to acid reflux in humans. Bile and stomach acid are naturally occurring fluids that aid in the digestion and processing of food. On an empty stomach, however, they can cause irritation. That irritation can lead an otherwise healthy and hungry dog to ignore meals, or, in more extreme situations, vomit to expel the excess. The vomit produced can be colored yellow, white, green, orange, brown, or some mixture, and is accompanied by slimy mucus.

Feeding an active dog smaller meals at regular intervals throughout the day — including a small snack first thing in the morning and last thing at night — may be the best and easiest way to address what could become a more serious problem. If excess stomach acid or bile are at fault, over the course of her life, a dog who produces excess digestive fluids can suffer from damage to her stomach or intestinal lining, leading to more serious digestive issues as she ages.

An alternate solution is acid-reducing medications. Consult with your dog’s veterinarian, who can recommend an antacid which may also help relieve your dog’s suffering, especially if your work schedule prevents you from being able to physically give your dog meals throughout the day.

3. Bloat

Bloat, also known as gastric torsion or stomach dilation, is an extremely serious condition in dogs. In the worst cases, a dog’s stomach literally becomes twisted from its normal position in the abdomen. This not only traps air, food, and fluids in the stomach, but it also restricts blood flow. One of its early symptoms, before all movement into and out of the stomach is cut off, is white foam in the dog’s vomit. This condition most commonly occurs in deep-chested adult and senior dogs. While the precise reasons for it are unclear, prevention consists mainly of making sure dogs are not overactive just after meals.

Two dogs playing together.

Contracting a virus can cause dogs to vomit white foam. (Photo by Pixabay)

4. Kennel cough

Kennel cough is a mild illness, most commonly contracted in multi-dog households, at boarding facilities, veterinary offices, dog parks, and places where training classes are held. Wherever a large number of dogs are present, this upper respiratory infection can strike. If a vomiting dog who produces white foam has recently been in one of these situations, a veterinarian may reach a diagnosis much more quickly. Other symptoms to look out for are a hacking cough and discharge around the eyes and nose. Kennel cough also tends to be a self-limiting sickness, typically running its course in about two weeks.

5. Pancreatitis

Swelling or inflammation of the pancreas interrupts a dog’s normal digestive functioning. When food cannot be properly and regularly broken down, processed, and eliminated, the dog’s options for getting rid of the excess material in its stomach are limited. Vomiting is one route, and white foam can accompany it. Dogs with diabetes are at increased risk for developing pancreatitis, which is when white foam in the vomit is also linked to diabetes. Other symptoms include adopting a hunched-over position, noticeable abdominal pain, and fever.

6. Parvovirus

A viral infection seen most frequently in puppies and very young dogs who live in multi-dog homes, parvo is transmitted through oral contact with feces. Signs of this illness generally begin within a week to 10 days of exposure to the virus. Along with vomit, the most alarming symptom of parvo is diarrhea that contains blood and has a strong odor. This is a deadly disease; however, most early-life combination vaccines help puppies build up immunity to parvovirus. Foamy vomit in an unvaccinated dog may indicate parvo as the cause, and a veterinarian should be consulted as soon as possible.

7. Rabies

Rabies is the last, and least likely, culprit for vomit with foam. We’re all familiar with the image of a rabid dog foaming at the mouth, but regurgitating foam only happens in the very last stages. By the time a dog takes to puking a foamy substance, observers will have noticed much more worrisome signs, such as aggressive behavior. As with parvo, rabies is preventable with the appropriate vaccines and boosters.

A dog in for a vet checkup.

If dog vomiting persists for more than a day, consult a veterinarian. (Photo by Shutterstock)

Why is my dog throwing up white foam? There are many reasons and many solutions:

An informed, observant, and proactive dog owner has a distinct advantage. This means knowing your dog’s eating habits, noting any deviations, and being able to adjust as circumstances require. Changing the portions and frequency of a dog’s meals, whether she is a growing puppy or an active adult, can help prevent the buildup of bile and acid, which causes later-life digestive problems.

Keeping a dog in a clean environment — including regularly sanitized food and water bowls — minimizes the risk of contracting parasites as well as bacterial infections. The two most dangerous reasons why a dog might spew white foam — parvo and rabies — are largely preventable with proper vaccination.

About the author: Melvin Peña trained as a scholar and teacher of 18th-century British literature before turning his research and writing skills to puppies and kittens. He enjoys making art, hiking, and concert-going, as well as dazzling crowds with operatic karaoke performances. He has a one-year-old female Bluetick Coonhound mix named Idris, and his online life is conveniently encapsulated here.