When your dog suddenly stops eating and begins vomiting, it can be alarming and distressing. These symptoms may indicate anything from a mild stomach upset to a potentially life-threatening condition.
We outline the common causes of a dog suddenly not eating and vomiting, what you can do at home, and when to seek veterinary help.
Table of Contents
Dog Suddenly Not Eating and Vomiting — Why It Happens
A sudden loss of appetite combined with vomiting often points to a disruption in your dog’s digestive or systemic health. This can be triggered by gastrointestinal upset, toxin ingestion, infections, pancreatitis, or blockages.
Sometimes, stress or dietary indiscretion are the underlying causes. In other cases, it can indicate more serious conditions like organ dysfunction or endocrine issues.
Common Causes of Dog Suddenly Not Eating and Vomiting
Gastroenteritis
Gastroenteritis is the inflammation of the stomach and intestines, often caused by bacteria, viruses, or spoiled food.
It leads to vomiting, diarrhea, and a disinterest in food. Dogs may appear lethargic and uncomfortable, and dehydration can occur quickly if vomiting persists.
This condition is especially concerning if it happens suddenly and your dog refuses food for more than a day.
Related: Dog shaking and vomiting (Why it happens)
Ingesting Something Toxic or Foreign
Dogs are curious creatures and may ingest toxic substances (like chocolate, certain plants, or medications) or foreign objects (toys, bones, clothing).
These can cause gastrointestinal irritation or blockages, both of which lead to vomiting and appetite loss. Some toxins also affect the liver or kidneys, worsening the situation.
Vomiting may begin suddenly and be followed by other symptoms like drooling, tremors, or collapse.
Pancreatitis
Pancreatitis is an inflammation of the pancreas, often triggered by high-fat meals, obesity, or certain medications.
Affected dogs commonly vomit, act lethargic, and avoid food. They may also exhibit abdominal pain (arched back, reluctance to move).
This is a serious and painful condition that requires veterinary treatment.
Intestinal Obstruction
A foreign body stuck in the digestive tract can block food passage and cause severe symptoms.
Vomiting is usually persistent and non-productive (dry heaving), and the dog may become very weak and refuse all food or water.
Obstructions can be life-threatening and may require emergency surgery.
Kidney or Liver Disease
Organ dysfunction affects how the body filters waste and digests food.
Vomiting and appetite loss are early signs of kidney or liver disease, especially in older dogs. These dogs may also drink more water or urinate excessively.
If untreated, these diseases can progress and cause permanent damage.
Read more: Dog Suddenly Limping and Not Eating (What it means)
Viral or Bacterial Infections
Parvovirus, leptospirosis, and bacterial infections like salmonella can all cause vomiting and anorexia.
Young dogs or unvaccinated pets are especially vulnerable. These infections often cause additional symptoms like diarrhea, fever, and weakness.
Rapid veterinary care is critical, particularly for parvo or leptospirosis.
Puppy Suddenly Not Eating and Vomiting
When a puppy suddenly stops eating and starts vomiting, it’s often a sign of infection, parasites, or that the puppy ate something harmful. Puppies have delicate digestive systems, and even small disturbances can cause vomiting.
However, serious conditions like parvovirus or intestinal blockage must be ruled out immediately, as they can become life-threatening quickly.
Because puppies dehydrate fast, any vomiting combined with refusal to eat for more than a few hours requires urgent veterinary attention.
Old Dog Suddenly Not Eating and Vomiting
If an older dog suddenly refuses food and vomits, it could indicate underlying illnesses such as kidney or liver disease, pancreatitis, or even cancer.
Aging dogs are more prone to internal organ issues that upset the stomach or cause nausea.
Occasionally, pain from dental disease or medication side effects may also be to blame.
Since senior dogs have less energy and slower recovery, it’s important to visit a vet promptly to identify the cause and prevent dehydration or decline.
Dog Suddenly Not Eating and Vomiting Bile
Vomiting bile, a yellow or greenish fluid, usually means your dog’s stomach is empty and irritated. This can happen if your dog goes too long without food, eats too fast, or suffers from conditions like acid reflux, gastritis, or pancreatitis.
The refusal to eat may result from the nausea bile causes. Feeding smaller, more frequent meals can help mild cases, but if vomiting bile persists or your dog seems weak, seek veterinary care to rule out more serious gastrointestinal issues.
Dog Suddenly Not Eating and Vomiting and Diarrhea
A dog that suddenly stops eating and develops vomiting and diarrhea likely has a significant digestive disturbance caused by infection, food poisoning, or ingesting something toxic.
This combination leads to rapid fluid loss and can quickly cause dehydration. While mild cases may resolve within 12–24 hours, persistent symptoms signal a serious illness such as parvovirus or pancreatitis.
Immediate veterinary evaluation is crucial to determine the cause, prevent complications, and start fluid and supportive treatment.
What to Do If Your Dog Is Suddenly Not Eating and Vomiting
Start by withholding food for 12–24 hours, but make sure your dog has access to clean water. This allows the stomach to rest.
After the fasting period, you can offer a bland diet (like plain boiled chicken and white rice) in small portions. If vomiting continues, stop feeding and contact your vet.
Keep your dog calm and monitor for other symptoms such as lethargy, diarrhea, bloating, or signs of pain. Avoid giving any human medications without veterinary guidance.
If your dog vomited only once and seems otherwise fine, it’s okay to observe. But if vomiting is repeated or your dog refuses food for more than 24 hours, it’s time to seek help.
When to Call or Visit Your Vet
Vomiting accompanied by refusal to eat should not be ignored, especially if it’s sudden and persists.
Contact your vet immediately if:
Vomiting occurs more than once in 24 hours
Your dog refuses food or water for more than 24 hours
There is blood in the vomit or stool
Your dog is lethargic, bloated, or in pain
Gums are pale, white, or blue
Your dog shows signs of dehydration (dry gums, sunken eyes)
Prompt intervention can prevent complications and lead to faster recovery.
Read more: Dog Sick and Not Eating and Vomiting (When to worry)
Key Takeaway
Sudden vomiting combined with loss of appetite can signal anything from a minor issue to a serious medical emergency.
Observe your dog closely, offer small amounts of bland food if appropriate, and don’t delay veterinary care if the symptoms persist or worsen.
Acting quickly can make a big difference in your dog’s comfort and outcome.