Why Is My Dog Throwing Up White Foam?

White, frothy vomit looks alarming, but on its own it tells you less than you might think. Foam is simply fluid that has been churned with air, usually saliva and stomach juices, and it can come up for very ordinary reasons. The useful questions are how it came up, how often, and how your dog is in between.

This guide covers the common causes, the one pattern that is a true emergency, what you can do at home, and when to call your vet.

What white foam actually is

When the stomach has little or no food in it, what remains is mostly saliva, mucus and stomach acid. If the stomach is irritated and empties itself, that thin liquid is whipped with air on the way up and comes out as white foam. If a little bile is mixed in, the foam turns yellow. See dog throwing up yellow for that pattern.

The same foam can also come from the airway rather than the stomach. A dog with an irritated throat or windpipe may cough hard, gag, and bring up a small amount of foamy saliva. Owners very often describe this as vomiting, which is why watching what happens just before the foam appears matters so much.

First, work out whether it is vomiting or coughing

• Vomiting from the stomach usually comes with warning signs (lip-licking, drooling, swallowing) then rhythmic heaving of the belly, and the foam lands in a puddle.
• Coughing and gagging starts with a cough, often a harsh honk, and ends with a retch and a small amount of foam, sometimes just a mouthful that the dog swallows again.

If it is the second, the cause is more likely to be in the throat or lungs. Read dog coughing and gagging and kennel cough symptoms instead.

Common causes of white foam vomit

• An empty stomach. Like bile vomiting, foam often appears first thing in the morning or late at night, when the stomach has been empty for many hours.
• Gastritis and gastroenteritis. Eating rubbish, rich food, grass or something new can irritate the stomach. Viral or bacterial infections and parasites cause the same picture, often with diarrhea.
• Acid reflux. Some dogs have stomach acid washing up into the oesophagus, which can cause foamy regurgitation, lip-licking and gulping, especially after lying down.
• Pancreatitis, often after a fatty meal, usually with belly pain, hunching and lethargy.
• A swallowed object partly blocking the stomach or intestines. Once the stomach has emptied of food, the vomit is often just foam.
• Kennel cough and other airway problems, where the foam follows a cough.
• Poisoning. Many toxins cause drooling and vomiting. If there is any chance your dog ate something toxic, see dog poisoning and first steps and call your vet.
• Bloat (gastric dilatation-volvulus). This is the cause you must not miss, covered next.

The emergency: bloat

In bloat, the stomach fills with gas and can twist on itself, trapping the gas and cutting off blood supply. One of the earliest signs is repeated retching that produces only white foam or nothing at all, together with restlessness, drooling, pacing and a belly that becomes swollen and tight. Some dogs stand with their front legs down and back end raised, or look repeatedly at their side.

Bloat can kill within hours and needs surgery. It is most common in large, deep-chested breeds (Great Danes, German Shepherds, Standard Poodles, Weimaraners, Setters and similar) but can happen to any dog. If you see this pattern, do not wait to see whether it settles. Go to the nearest vet or emergency clinic immediately.

When to call the vet

Puppies, older dogs and dogs with existing illness should be seen sooner, because they dehydrate faster and have less in reserve. The same applies to any dog that has recently had surgery, started a new medicine, or might have got into the bin, the garden shed or a handbag. Tell your vet about any of these when you call.

What you can do at home

For an otherwise healthy adult dog that has brought up foam once or twice and is bright and alert:

1. Hold food for a few hours, but offer small, frequent sips of water. Do not withhold food from puppies, toy breeds or diabetic dogs without your vet’s advice.
2. Restart with a small, bland, low-fat meal, such as plain boiled chicken and white rice, in several small portions through the day.
3. Avoid long empty-stomach gaps. If the foam tends to appear in the morning, try a small snack before bed and keep meals no more than about 12 hours apart.
4. Remove access to rubbish, toys that can be chewed into pieces, and anything toxic.
5. Write down what you see (times, what came up, whether it followed a cough) and take a short video if it happens again.

Do not give human medicines, and do not try to make your dog vomit unless a vet or poison line tells you to.

What the vet will do

Your vet will ask about the timing and appearance of the episodes, check whether it is vomiting or coughing, and examine your dog, paying particular attention to the belly, the throat and the chest. If the cause is not obvious they may recommend blood tests, X-rays or an ultrasound scan. Treatment depends on the cause: anti-nausea medicine and a bland diet for a simple stomach upset, medicine to reduce acid for reflux, fluids for dehydration, and emergency stabilisation and surgery for bloat.

For a broader look at vomiting of every kind, see dog throwing up: causes and when to worry, or browse the digestive health section.