Why Is My Dog Vomiting?
Vomiting is the most common reason dogs are taken to emergency vets. Here are the 14 most common causes, the difference between vomiting and regurgitation, emergency red flags, and when it is safe to monitor at home.
Dogs vomit more readily than almost any other domestic animal — it is a normal protective reflex that expels harmful substances from the stomach. This means occasional vomiting in an otherwise healthy dog is not always cause for alarm. However, vomiting can also be the first sign of serious or life-threatening conditions. Knowing the difference between 'wait and watch' and 'go to the vet now' is the most important thing a dog owner can understand about this symptom.
Vomiting vs. Regurgitation — Know the Difference
Vomiting
Active abdominal contractions — the dog heaves and retches before expelling stomach contents. Material is usually digested (may be bile-yellow, partially digested food, or foam). Vomiting involves effort and discomfort.
Regurgitation
Passive — material comes up without effort or heaving, often immediately after eating or drinking. Material is undigested, often tube-shaped from the esophagus. No abdominal contractions. Suggests an esophageal problem rather than a stomach problem.
This distinction matters because regurgitation suggests a different set of causes (megaesophagus, esophageal obstruction, or acid reflux) and requires different investigation. Tell your vet which you observed.
🚨 Go to Your Vet or Emergency Clinic Immediately If:
- •Your dog is vomiting and has a distended, hard, or painful abdomen (possible GDV/bloat — life-threatening within hours)
- •Vomiting more than 4–5 times in a few hours without stopping
- •There is blood in the vomit — bright red or dark coffee-ground appearance
- •Your dog is lethargic, weak, or collapsing between vomiting episodes
- •Your dog cannot keep water down for more than 4–6 hours
- •Vomiting is accompanied by diarrhea AND lethargy (possible parvovirus or hemorrhagic gastroenteritis)
- •Your dog has eaten something toxic, a foreign object, or a medication not prescribed to them
- •Your dog is a puppy under 6 months (dehydration is dangerous much faster in young dogs)
- •Your dog has a known health condition (diabetes, kidney disease, Addison's disease) and begins vomiting
- •Vomiting began after an anaesthetic or new medication
14 Common Causes of Vomiting in Dogs
These causes are ranked from most to least common in otherwise healthy adult dogs seen in general practice.
Dietary Indiscretion ('Garbage Gut')
Low riskThe most common cause of acute vomiting in dogs. Dogs eat things they shouldn't — rubbish, compost, dead animals, fatty human food scraps, or unknown objects. The stomach expels the offending material and the dog typically recovers within 12–24 hours. This is often called 'garbage gut' or 'dietary indiscretion.'
Symptoms:
1–3 vomiting episodes, may continue eating, otherwise normal energy and behavior. Resolves within 24 hours.
Action:
Withhold food for 4–6 hours. Offer small amounts of water frequently. If no improvement in 24 hours or symptoms worsen, call your vet.
Eating Grass
Low riskDogs commonly eat grass and then vomit. The exact reason is debated — some dogs seem to eat grass when feeling nauseous, others simply enjoy it. Occasional grass eating followed by vomiting in an otherwise healthy dog is generally not a concern. Frequent grass-eating and vomiting may indicate underlying gastrointestinal discomfort.
Symptoms:
Vomiting of grass and bile, often in the morning on an empty stomach. Dog appears normal otherwise.
Action:
Monitor. If the dog eats grass and vomits more than 2–3 times per week, discuss with your vet — may indicate acid reflux or IBD.
Gastroenteritis (Stomach Bug)
MonitorInflammation of the stomach and intestines, often from a viral or bacterial infection, a food sensitivity, or a sudden diet change. A very common cause of acute vomiting. Usually self-limiting but can cause rapid dehydration, especially in puppies.
Symptoms:
Vomiting, often with diarrhea, lethargy, reduced appetite. Typically lasts 24–72 hours.
Action:
Bland diet (boiled chicken and rice), small amounts of water frequently. Call your vet if symptoms last more than 48 hours, if blood is present, or if your dog becomes lethargic.
Foreign Body / Obstruction
CriticalDogs swallow socks, toys, bones, corn cobs, rocks, and countless other objects. A foreign body can cause partial or complete obstruction of the stomach or intestines — ranging from intermittent vomiting (partial obstruction) to rapid deterioration requiring emergency surgery (complete obstruction). This is one of the most dangerous causes of vomiting and one of the most common surgical emergencies in dogs.
Symptoms:
Repeated vomiting that does not resolve, especially after eating. Abdominal pain, hunching, restlessness. May still pass some stool in partial obstruction.
Action:
Emergency veterinary assessment. Do not wait. X-ray and possibly ultrasound to identify the object. Endoscopic or surgical removal required.
Bloat (Gastric Dilatation-Volvulus / GDV)
CriticalGDV is a life-threatening emergency where the stomach fills with gas and twists, trapping the contents and cutting off blood supply to the stomach and spleen. It can kill a dog within 2–6 hours if untreated. Deep-chested breeds (Great Danes, German Shepherds, Labradors, Dobermanns) are at highest risk, but any large dog can develop GDV. The vomiting in GDV is characteristically unproductive — the dog retches repeatedly without producing anything.
Symptoms:
Unproductive retching (trying to vomit but nothing comes up), rapidly distended hard abdomen, extreme restlessness and distress, pale gums, collapse.
Action:
This is an emergency — go to a vet immediately. Do not wait. Surgery required within hours.
Toxin or Poison Ingestion
CriticalVomiting is a common early sign of toxin ingestion — including xylitol, grapes, raisins, chocolate, mushrooms, rat poison, human medications (ibuprofen, paracetamol), garden plants (daffodils, azaleas), and many others. Do not wait for symptoms to worsen.
Symptoms:
Vomiting, may progress rapidly to lethargy, seizures, bleeding, liver or kidney failure depending on the toxin.
Action:
Emergency vet — bring the packaging or a sample if possible. Time is critical with most toxins. Do not induce vomiting without vet instruction.
Parvovirus (Puppies & Unvaccinated Dogs)
CriticalCanine parvovirus is a highly contagious, potentially fatal viral disease. It causes severe vomiting and hemorrhagic (bloody) diarrhea, leading to rapid dehydration and death within days if untreated. Puppies and unvaccinated dogs are most at risk. Vaccination is highly effective at prevention.
Symptoms:
Severe vomiting, bloody diarrhea, profound lethargy, loss of appetite, fever. Rapid deterioration.
Action:
Emergency veterinary care immediately. Intensive supportive treatment (IV fluids, anti-nausea medication, antibiotics) is required. Survival rates with aggressive treatment are good.
Kidney Disease (CKD or Acute Kidney Injury)
CriticalFailing kidneys allow toxins (urea, creatinine) to accumulate in the bloodstream — a condition called uremia. These toxins directly trigger the vomiting center in the brain. Chronic vomiting in a middle-aged or senior dog, especially accompanied by increased thirst and urination, should always prompt a kidney check.
Symptoms:
Chronic or recurring vomiting, often in the morning. Increased thirst and urination, reduced appetite, weight loss, bad breath (ammonia odor), lethargy.
Action:
Blood and urine tests. Kidney-supportive diet, hydration therapy, and medication to manage nausea.
Pancreatitis
High priorityInflammation of the pancreas — often triggered by a high-fat meal, dietary indiscretion, or certain medications. The pancreas releases digestive enzymes that begin digesting the organ itself, causing severe pain and systemic inflammation. A common presentation is a dog that ate a fatty meal (e.g. leftover roast meat) and develops vomiting 12–24 hours later.
Symptoms:
Vomiting, abdominal pain (hunched posture, reluctance to move), lethargy, diarrhea, reduced appetite. The 'praying position' (front legs stretched out, hindquarters raised) is a classic sign of abdominal pain.
Action:
Veterinary assessment. Blood tests (lipase). Hospitalization for IV fluids, pain management, and anti-nausea medication in moderate to severe cases.
Inflammatory Bowel Disease (IBD)
High priorityChronic inflammation of the gastrointestinal tract that impairs nutrient absorption and causes recurring vomiting, diarrhea, and weight loss. IBD in dogs is often under-diagnosed because symptoms are intermittent and mimic other conditions. Definitive diagnosis requires intestinal biopsy.
Symptoms:
Chronic or recurring vomiting (weeks to months), weight loss despite normal or increased appetite, intermittent diarrhea, gurgling bowel sounds.
Action:
Dietary trial (novel protein or hydrolysed diet), bloodwork, imaging, and possibly endoscopy and biopsy. Management with diet and/or immunosuppressive medication.
Diabetes & Diabetic Ketoacidosis (DKA)
CriticalUncontrolled diabetes causes a dangerous complication called ketoacidosis (DKA) — an accumulation of acidic ketone bodies in the blood that causes severe vomiting, lethargy, and rapid deterioration. DKA is an emergency. Vomiting in a known diabetic dog always requires urgent veterinary assessment.
Symptoms:
Vomiting, lethargy, loss of appetite, sweet or fruity breath odor (ketones), rapid breathing, collapse. Prior history of excessive thirst and urination.
Action:
Emergency veterinary care. IV fluids and insulin management. Do not adjust insulin dose without vet guidance.
Intestinal Parasites
MonitorHeavy worm burdens (roundworms, hookworms, whipworms) or Giardia infection can cause vomiting, particularly in puppies. Adult dogs with regular parasite prevention rarely vomit from worms alone, but it can occur if prevention has lapsed.
Symptoms:
Vomiting (sometimes containing visible worms), diarrhea, pot-bellied appearance (puppies), weight loss, dull coat.
Action:
Fecal examination. Appropriate anthelmintic (deworming) treatment. Monthly prevention medication.
Medication Side Effects
MonitorMany medications commonly given to dogs cause vomiting as a side effect — including NSAIDs (e.g. carprofen, meloxicam), antibiotics (particularly metronidazole), chemotherapy drugs, and some dewormers. Vomiting that starts within hours to days of starting a new medication is likely related.
Symptoms:
Vomiting beginning after starting new medication. May be accompanied by loss of appetite.
Action:
Contact your vet before stopping any medication. Never stop prescription medication without veterinary guidance. An alternative medication or anti-nausea medication may be prescribed.
Motion Sickness
Low riskMany dogs vomit during car travel due to motion sickness — the inner ear's balance signals conflict with visual input, triggering nausea. This is distinct from anxiety-related vomiting, though anxiety can compound it. Puppies are more susceptible; many improve as they mature.
Symptoms:
Vomiting during or shortly after car travel. May also drool excessively, yawn repeatedly, or appear distressed during travel.
Action:
Short acclimatisation journeys, travel on an empty stomach, ensure good ventilation. Prescription anti-nausea medication (maropitant / Cerenia) is very effective and available from your vet.
When Is It Safe to Monitor at Home?
A single vomiting episode in an otherwise alert, energetic adult dog with no blood, no abdominal distension, and no known toxin exposure can usually be monitored at home for 12–24 hours. Withhold food for 4–6 hours, offer small amounts of water, and reintroduce a bland diet (boiled chicken and plain rice, 1:3 ratio) for 24–48 hours before transitioning back to normal food. Call your vet if the dog vomits again, becomes lethargic, refuses water, or shows any of the emergency signs listed above.
Vomiting Timeline — When to Act
Monitor at home. Withhold food 4–6 hours. Offer water in small amounts. Bland diet when reintroducing food.
Call your vet for advice. Monitor closely for emergency signs. Do not feed for 6+ hours.
See your vet today — same day appointment. Risk of dehydration and underlying serious cause.
Go to vet or emergency clinic immediately. Do not wait.
Monitor Your Dog After a Vomiting Episode
After a vomiting illness, your dog may lose body condition. PawScan's photo scan gives an instant body condition score to help you track recovery and notice if weight loss is occurring.
Scan your pet nowFrequently Asked Questions
Should I be worried if my dog vomits once?▾
A single vomiting episode in an otherwise healthy, alert adult dog is usually not cause for immediate alarm. Monitor for 12–24 hours — withhold food for 4–6 hours, offer small amounts of water, and watch for emergency signs (lethargy, blood, distended abdomen, repeated vomiting). If your dog vomits again or shows any concerning signs, call your vet.
Why does my dog vomit bile in the morning?▾
Morning vomiting of yellow bile — often on an empty stomach — is a common pattern in dogs. It is usually caused by bilious vomiting syndrome, where bile from the small intestine refluxes into the empty stomach overnight, causing irritation. Management: feed a small meal last thing at night before bed to prevent the stomach being empty for too long. If it continues, discuss with your vet — acid-reducing medication is often effective.
Is it normal for dogs to eat grass and vomit?▾
Grass eating and occasional vomiting is very common in dogs and not always a concern. Some dogs eat grass when nauseous; others simply enjoy it. If your dog eats grass and vomits occasionally without any other symptoms, it is usually not worrying. Frequent grass eating and vomiting (more than 2–3 times per week) may indicate underlying GI discomfort — worth mentioning to your vet.
What should I feed a dog that has been vomiting?▾
After a vomiting episode, withhold food for 4–6 hours to allow the stomach to settle. Then offer small amounts of a bland diet — boiled skinless chicken breast and plain white rice in a 1:3 ratio (1 part chicken, 3 parts rice). Feed small frequent portions (4× daily) for 24–48 hours before gradually transitioning back to your dog's normal food over 3–5 days.
What does it mean if my dog's vomit is yellow?▾
Yellow or greenish vomit is typically bile — a digestive fluid from the small intestine. It appears when the stomach is empty and bile refluxes upwards. This is most commonly seen in the morning (bilious vomiting syndrome) or when a dog has been vomiting repeatedly and has expelled all stomach contents. Occasional yellow bile vomiting is not usually serious. Frequent or persistent yellow vomiting warrants a vet assessment.
My dog vomited blood — what should I do?▾
Blood in vomit always requires prompt veterinary attention — do not wait. Bright red blood suggests active bleeding in the stomach or esophagus. Dark brown or 'coffee ground' appearance indicates older digested blood. Causes range from stomach ulcers (often medication-related) to hemorrhagic gastroenteritis, foreign bodies, or more serious systemic disease. Go to your vet or emergency clinic the same day.
This article is for educational purposes only. Always consult a licensed veterinarian for medical advice specific to your pet.