If your dog is not eating and throwing up foam, it can be a worrying sign of an underlying health issue. Understanding why dogs exhibit these symptoms and knowing what to do can help you protect your pet and get the right care quickly.
We outline why a dog might stop eating and throw up foam, the possible causes behind these symptoms, and when it’s critical to seek veterinary help.
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Here’s why a dog is not eating and throwing up foam
A dog not eating and throwing up foam often signals an underlying issue with your dog’s digestive system or overall health. Foamy vomit, especially white or yellow in color, is typically a mixture of stomach acid and saliva, and can occur when a dog’s stomach is empty for too long—leading to bile reflux or acid buildup.
However, if your dog is also refusing to eat, it may point to more serious problems like gastritis, pancreatitis, intestinal blockage, toxin ingestion, or even kidney or liver disease.
What does it mean when a dog throws up foam?
Throwing up foam in dogs often occurs when the stomach is empty. The foam consists mainly of mucus mixed with stomach acids, and this vomiting is sometimes called “bile vomiting” or “foam vomiting.” This can happen for several reasons:
Empty stomach irritation: When a dog hasn’t eaten for several hours, the build-up of stomach acids irritates the stomach lining, causing them to vomit foam.
Gastrointestinal distress: Conditions like gastritis or acid reflux can cause dogs to throw up foam.
Blockages or obstructions: Foreign objects or intestinal blockages may cause vomiting, often foamy in appearance.
Other medical conditions: Diseases affecting the liver, pancreas, kidneys, or infections can trigger foamy vomiting.
Common causes of dog not eating and throwing up foam
1. Gastrointestinal irritation or upset
The most common cause of a dog not eating and throwing up foam is irritation of the stomach lining or inflammation of the gastrointestinal tract.
This irritation may result from eating spoiled food, sudden dietary changes, or ingesting things they shouldn’t—like grass, dirt, or non-food items.
The stomach responds by producing more mucus and acid to try and protect itself, which leads to the production of foam.
This foam then gets vomited because the irritated stomach contracts to rid itself of the irritants.
Additionally, dogs with gastritis (inflammation of the stomach lining) or enteritis (inflammation of the intestines) often experience nausea, loss of appetite, and vomiting foam or bile.
This condition can result from infections, allergies, or autoimmune diseases.
Related: Dog not eating and pooping blood (Here’s why)
2. Empty stomach or acid reflux
Many dogs vomit foam in the morning or late at night when their stomachs are empty for several hours.
Without food, the stomach produces acid and bile that irritate the lining, causing the dog to vomit a foamy substance.
This situation can be likened to acid reflux in humans, where stomach acid irritates the esophagus and stomach lining.
Dogs may vomit foam repeatedly if they do not eat for prolonged periods, which can lead to nausea and discomfort, causing a loss of appetite.
Feeding smaller meals more frequently or providing a late-night snack can sometimes help reduce this foam vomiting caused by an empty stomach.
3. Stress and anxiety
Stress doesn’t just affect humans; it can also cause physical symptoms in dogs, including digestive upset.
When a dog is stressed, their body releases hormones like cortisol that can increase stomach acid production and affect gut motility, leading to vomiting foam and loss of appetite.
Stressful triggers might include:
Moving to a new home.
Introduction of new family members or pets.
Loud noises such as fireworks or thunderstorms.
Changes in routine or separation anxiety.
A stressed dog may also exhibit pacing, excessive licking, drooling, whining, or hiding alongside vomiting and refusal to eat.
Related: Dog not eating and stomach gurgling (Here’s why)
4. Infections and illnesses
Viral or bacterial infections are frequent causes of vomiting and loss of appetite in dogs.
Canine parvovirus, for example, is a serious viral infection in puppies that causes severe vomiting (often foamy or bile-stained), diarrhea, dehydration, and lethargy.
Other infections such as bacterial gastroenteritis or parasites like giardia can inflame the digestive tract and cause a dog to vomit foam and refuse food.
Infections cause the stomach lining and intestines to become inflamed, which leads to increased acid and mucus production, triggering vomiting.
Additionally, the body’s immune response to infection often results in decreased appetite.
5. Pancreatitis
Pancreatitis, or inflammation of the pancreas, is a severe and sometimes life-threatening condition.
It causes abdominal pain, vomiting (which can include foam or bile), diarrhea, lethargy, and refusal to eat.
The pancreas produces digestive enzymes, and when inflamed, these enzymes attack the pancreas itself, causing tissue damage.
This inflammation also disrupts digestion and causes nausea, leading to vomiting foam and loss of appetite.
Dogs with pancreatitis may appear very uncomfortable, often adopting a hunched posture, whining, or refusing to move.
6. Kidney or liver disease
Chronic kidney or liver disease can cause nausea and vomiting in dogs.
The buildup of toxins due to failing kidneys or liver affects the gastrointestinal tract, leading to symptoms such as vomiting foam, poor appetite, weight loss, and lethargy.
These diseases can disrupt the normal balance of fluids and electrolytes in the body, contributing to increased nausea and vomiting.
Because these are chronic diseases, symptoms may develop gradually and worsen over time, so any persistent vomiting foam accompanied by appetite loss in older dogs should prompt a vet visit.
7. Foreign body ingestion or intestinal blockage
Dogs are curious and often swallow things they shouldn’t, like toys, bones, or clothing.
If swallowed objects get stuck in the digestive tract, they cause a blockage that leads to vomiting, often foamy or bile-like.
An intestinal blockage is an emergency because it prevents food and fluids from passing, leading to severe vomiting, dehydration, abdominal pain, and lethargy.
Repeated vomiting foam, refusal to eat, and signs of discomfort (restlessness, whining, or bloating) require immediate veterinary attention.
8. Medication side effects or poisoning
Certain medications can irritate the stomach or cause nausea, resulting in a dog not eating and throwing up foam.
For example, some antibiotics or painkillers may cause digestive upset.
Poisoning from toxic substances such as household cleaners, poisonous plants, human medications, or contaminated food also causes vomiting foam, loss of appetite, diarrhea, and more severe symptoms like seizures or collapse.
If you suspect poisoning, immediate veterinary care is crucial.
Related: Dog eating grass and not eating (Here’s why)
Signs to watch for when your dog is not eating and throwing up foam
When your dog shows these symptoms, look carefully for additional signs that can indicate the severity of the issue:
Lethargy or weakness: Your dog may be unusually tired, reluctant to move, or sleepy.
Diarrhea: Watery or bloody stools often accompany vomiting foam, signaling digestive distress.
Excessive drooling: Usually occurs before vomiting.
Abdominal pain: Watch for whining, restlessness, or a hunched posture.
Dehydration: Signs include dry gums, sunken eyes, and poor skin elasticity.
Repeated vomiting: Vomiting more than twice or vomiting that worsens.
Weight loss: If the dog refuses food for days.
Behavior changes: Such as hiding, pacing, whining, or aggression.
What to do if your dog is not eating and throwing up foam
1. Monitor symptoms carefully
If your dog vomits foam once but acts normally otherwise, it might be a mild upset. Monitor them closely for worsening symptoms.
Make sure fresh water is available to avoid dehydration.
2. Withhold food for a short time
Temporarily withholding food (about 12 hours) allows the stomach to rest and reduce acid buildup.
Always provide small amounts of water during this fasting period to keep hydration levels up.
3. Reintroduce bland food slowly
After fasting, start feeding small amounts of bland food like boiled chicken and rice.
This diet is easy to digest and can help soothe the stomach. Gradually increase food quantity as long as vomiting doesn’t return.
4. Keep your dog hydrated
Vomiting leads to fluid loss and dehydration, which is dangerous, especially in puppies and older dogs. Encourage drinking small sips of water frequently, or offer ice cubes.
5. Avoid sudden diet changes
If the vomiting started after a new diet, revert to the old food and transition gradually over 7–10 days when introducing new food.
6. Remove access to toxins or foreign objects
Ensure your dog cannot reach harmful substances or small objects to prevent poisoning or blockage.
When to seek veterinary care
Seek immediate veterinary attention if:
Vomiting foam lasts more than 24 hours.
Vomiting occurs with diarrhea or blood.
Your dog shows severe lethargy or pain.
Dehydration signs appear.
Abdominal swelling or discomfort.
Your dog refuses all food and water.
Suspected poisoning or toxin ingestion.
Puppies, senior dogs, or dogs with other illnesses show these signs.
How to prevent dog not eating and throwing up foam
Provide a high-quality balanced diet tailored to your dog’s needs.
Avoid sudden dietary changes.
Keep dangerous toxins, plants, and objects out of reach.
Maintain routine vet visits.
Manage stress and anxiety through stable routines.
Monitor your dog’s health and appetite daily.
Key Takeaway
Vomiting foam combined with refusal to eat is a sign of gastrointestinal upset that requires your attention.
While it could be something as simple as an empty stomach or mild indigestion, it might also signal a serious issue such as pancreatitis, a foreign body obstruction, or kidney disease.
The key is to look at the full picture. If your dog throws up foam once but seems fine afterward, it’s likely a minor issue.
But if they continue vomiting, stop eating completely, show signs of pain, or act lethargic, don’t wait—call your veterinarian immediately.
The sooner you identify and address the cause, the better the outcome for your pet.