What this means
Foam appears when a dog vomits on an empty stomach: saliva, mucus and a little stomach fluid come up and whip into froth. That is why it is often seen in the morning or after a long gap between meals. The colour is not a diagnosis. What matters more is how your dog is behaving and how often it happens.
It is important to tell vomiting apart from unproductive retching. If your dog tries to vomit several times and nothing, or only a little foam, comes up while the belly looks swollen, this may be an emergency. Do not wait for it to settle on its own.
It helps to note when your dog last ate, how many times it vomited, whether it was calm between bouts and whether there was coughing as well. A cough that ends in bringing something up can look like vomiting even though it starts in the airways. A short video is more useful to your vet than a description in words.
Possible causes
These are things that can cause this sign. It is not a diagnosis, and they are not equally likely for your dog.
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An empty stomach
After a long gap between meals, fluid and mucus build up in the stomach and the dog vomits them. If it happens rarely and your dog stays bright and keeps eating, there is usually little to worry about.
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Inflammation of the stomach or intestines
An inflamed gut lining can cause foamy vomiting, especially when it repeats. Changed stools or a poor appetite are sometimes seen alongside.
About the condition: Gastroenteritis -
Stomach bloat and twisting
This is an emergency, typically showing as unproductive retching, drooling and a swollen belly. Larger, deep-chested dogs are especially at risk.
About the condition: Bloat (gastric dilatation-volvulus) -
Inflammation of the pancreas
An inflamed pancreas causes vomiting, belly pain and lethargy. Your dog may stand stretched out and object to the belly being touched.
About the condition: Pancreatitis -
Airway problems that look like vomiting
A weak windpipe or another airway problem causes a cough after which your dog spits up foam. It looks like vomiting but starts elsewhere, so note whether coughing came first.
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- When your dog last ate and how many times it vomited
- Whether anything really comes up, or it only retches
- Whether there was coughing or choking sounds beforehand
- Whether the belly is swollen, hard or sore to touch
- Whether your dog drinks and keeps the water down
- Whether your dog is bright, or restless and drooling
When to book a routine visit
Book a visit if foamy vomiting carries on for several days, if your dog is flat or off its food, if it returns every few weeks or if it often looks like a cough. If any of the urgent signs above appear, go straight away rather than waiting for an appointment.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
- Bloat (gastric dilatation-volvulus) Digestion and liver This is a condition in which the stomach fills with gas and can twist around on itself, pinching off its blood vessels and cutting off circulation. It develops very quickly and is life-threatening, so the dog needs a vet immediately. Large, deep-chested dogs are known to be at risk, so it is worth noting the number of the nearest emergency clinic in advance.
- Pancreatitis Digestion and liver Pancreatitis is inflammation of the pancreas, in which digestive enzymes become active too early and start to irritate the pancreas itself and the tissue around it. It can come on suddenly or smoulder for a long time with repeated flare-ups, and in more severe cases it affects other organs too. The causes vary, so working out what is going on with a particular dog is a job for the vet.
- Inflammatory bowel disease (IBD) Digestion and liver This is a long-term disorder of the digestive tract in which inflammatory cells build up in the wall of the stomach or intestine, so it becomes less able to digest food and absorb nutrients. The exact cause is not fully understood; an interplay between the immune system, gut bacteria and food is thought to play a part. Because many other digestive problems look much the same, a vet works out what is really going on with tests.
- Tracheal collapse Breathing Tracheal collapse is a condition in which the cartilage rings of the windpipe weaken and the windpipe flattens, making it harder for air to reach the lungs. It tends to get slowly worse over time, and excitement, heat, pressure on the neck or excess weight can make breathing even harder.
- Kennel cough Infections Kennel cough is a contagious inflammation of the upper airways caused by one or more viruses and bacteria. Dogs catch it wherever many dogs meet: boarding kennels, training grounds, shows or popular walking spots. The dog has a loud, dry cough but may stay bright; what caused the cough is for a vet to establish.
Body systems: Digestion and liver Breathing Infections