Dog & cat health · Vet-reviewed guide

Dog Vomiting: Causes and When to Worry

Dogs vomit for reasons that range from 'ate grass' to 'get to a vet now.' The color, the frequency, and how your dog is otherwise doing are what sort it out.

Quick answer: Dog vomiting once, in a dog that is otherwise bright and eating, is often nothing serious — but repeated vomiting, or vomiting with other signs, is a reason to see a vet. A single upset stomach from eating too fast or something disagreeable usually passes.

What changes the picture is frequency and company: vomiting three or more times in a day, vomiting you cannot stop, or vomiting alongside blood, a bloated belly, diarrhea, or a low, flat dog all point to a real problem. Two dog emergencies deserve special mention: a swollen, hard belly with unproductive retching can mean bloat, which is life-threatening within hours, and vomiting plus bloody diarrhea in a young or unvaccinated dog can mean parvo. This guide covers the common causes, what the vomit can tell you, and the clear signs that mean go to a vet now.

Emergency: Go to a vet immediately if your dog has a swollen or hard belly and is retching without bringing anything up (possible bloat), is vomiting blood, is vomiting repeatedly with bloody diarrhea (possible parvo), or is weak, collapsing, or unable to keep water down.

About Cerenia (maropitant): this is a prescription medication your veterinarian can prescribe. Read our guide, or ask us if you need help sourcing it.

When vomiting is probably okay

One episode in a dog that quickly returns to normal, eats, drinks, and acts like itself is often not a concern.² Dogs vomit fairly readily, and a single bout after scarfing food, a diet change, or a bit of grass usually settles on its own.

When to worry

See a vet when vomiting is repeated (three or more times in a day), will not stop, or comes with any of: blood, a bloated or painful belly, diarrhea, lethargy, refusing water, or a known toxin exposure.¹ Puppies, senior dogs, and unvaccinated dogs should be seen sooner, as they go downhill faster.

Dog-specific emergencies to know

• Bloat (GDV). A swollen, tight belly with unproductive retching, drooling, and restlessness is a life-threatening emergency, most common in large, deep-chested breeds. Do not wait; go to an emergency vet.²
• Parvovirus. Vomiting with bloody diarrhea and lethargy, especially in a puppy or unvaccinated dog, can be parvo, which is fatal without fast treatment.

A word on making a dog vomit

If your dog has swallowed something dangerous, do not reach for a home method to make it vomit on your own. For some poisons, vomiting makes the harm worse, and the wrong approach can injure your dog.² Call your vet or the ASPCA Animal Poison Control Center first and follow their specific instructions. The safe move is a phone call, not a guess.

What the vomit can tell you

Color is a clue, not a diagnosis. Yellow usually means bile on an empty stomach; white foam often means an empty, irritated stomach; blood, whether red or dark like coffee grounds, needs a vet. See our guides on yellow vomit, white foam, and vomiting blood. If diarrhea is also involved, see dog diarrhea.

What the vet does

A vet examines your dog, may run tests or imaging to find the cause, and treats accordingly, from fluids and anti-nausea medicine to treating an underlying disease.¹ Any prescribed medicine must be chosen by a vet. See how our vet prescription service works.