If you’ve noticed your dog suddenly drooling excessively and then throwing up, you may be wondering what’s going on.
We outline why dogs drool before vomiting, what causes this strange pattern, and when it’s time to worry.
Here’s Why Dogs Drool Before Vomiting
Drooling before vomiting in dogs is often an early warning sign that your dog is feeling nauseous. Just like humans may salivate when they’re about to vomit, dogs produce extra saliva before throwing up as part of their body’s preparation to purge something unpleasant from their stomach.
This pre-vomiting drooling is commonly caused by gastrointestinal upset, ingestion of toxins, motion sickness, stress, or underlying illnesses. While some occasional drooling followed by vomiting might not be serious, frequent episodes can be a red flag that shouldn’t be ignored.
Why Do Dogs Drool Before Vomiting? Common Causes
1. Nausea and Gastrointestinal Discomfort
One of the most common reasons dogs drool before vomiting is simple: nausea.
Nausea in dogs triggers excessive salivation as a way to protect the esophagus and mouth lining from stomach acids during vomiting.
Causes of nausea can range from:
Eating spoiled or indigestible food
Sudden changes in diet
Motion sickness during car rides
Gastrointestinal infections from bacteria or parasites
Before a dog throws up, their salivary glands ramp up saliva production.
This excessive drooling is a natural way to prepare the body for vomiting.
If your dog is also licking their lips, smacking, swallowing frequently, or pacing—these are further signs of nausea to watch for.
2. Ingestion of Toxins or Foreign Objects
Dogs explore the world with their mouths, and sometimes they eat things they shouldn’t—like human medications, household cleaners, chocolate, grapes, or even random objects like socks or toys.
If a dog consumes something toxic or indigestible, their body responds by trying to eject it.
Before vomiting, the body initiates a defense mechanism, and drooling in dogs before vomiting is one of the first signs.
The extra saliva helps protect their digestive tract during the vomiting process and often appears within minutes of ingesting something harmful.
If your dog is drooling and vomiting and you suspect they’ve eaten something toxic, seek veterinary care immediately.
Related: Dog drooling throwing up and diarrhea (Explained)
3. Motion Sickness
Motion sickness in dogs, especially puppies and younger dogs, is a frequent cause of dog drooling before vomiting in the car.
The disorientation and nausea triggered by motion can cause hypersalivation long before the dog actually vomits.
In this situation, symptoms may include:
Drooling excessively
Panting or restlessness
Whining
Trying to lie down or find a corner
Vomiting mid-ride or shortly after
To help your dog cope with motion sickness, you can ask your vet about anti-nausea medications or slowly conditioning them to tolerate car rides.
4. Stress and Anxiety
Stress can be a silent trigger behind drooling and vomiting in dogs.
When a dog is anxious—whether due to thunderstorms, separation, loud noises, or unfamiliar environments—their body goes into a state of fight-or-flight.
One physical response is an increase in saliva production, which may lead to drooling.
Chronic stress can also disrupt your dog’s digestive system, causing vomiting. Common stress-related behaviors that appear before vomiting include:
Whining
Hiding
Pacing or shaking
Licking or chewing paws
Stress-induced drooling is not always followed by vomiting, but when it is, it’s usually paired with other behavioral changes.
Identifying the stressor is essential to help your dog feel better and avoid repeated episodes.
5. Mouth or Throat Issues
Dogs suffering from dental problems, oral infections, or throat injuries may start to drool excessively.
If the pain or discomfort becomes severe, they might also vomit.
Conditions that can lead to drooling before vomiting include:
Gum disease or tooth abscess
Foreign objects lodged in the throat
Tonsillitis
Mouth ulcers or burns from chewing on caustic items
Drooling in these cases is usually accompanied by bad breath, difficulty eating, or pawing at the mouth.
If your dog is showing these signs, a vet visit is necessary to inspect their oral health.
Related: Dog throwing up and drooling (Explained)
6. Heatstroke or Overheating
Heatstroke is a potentially deadly condition in dogs that can cause excessive drooling followed by vomiting.
Dogs regulate their body temperature through panting, but when they overheat, their body may begin producing too much saliva as a symptom of distress.
Look out for the following heatstroke symptoms:
Heavy panting and drooling
Vomiting or diarrhea
Bright red gums or tongue
Lethargy or collapse
Immediate veterinary care is critical in cases of heatstroke.
Always keep your dog cool and well-hydrated, especially during summer months or after exercise.
7. Liver or Kidney Disease
Another potential reason why dogs drool before vomiting is due to systemic illness, such as liver disease or kidney failure.
These conditions cause a buildup of toxins in the bloodstream, leading to nausea, vomiting, and hypersalivation.
Symptoms to watch for:
Lethargy
Loss of appetite
Bad breath
Increased thirst and urination
Yellowing of eyes or gums (jaundice)
If you notice these symptoms along with your dog drooling and vomiting, it could be an indicator of an underlying disease, and blood tests at the vet will be required.
What To Do If Your Dog Drools Before Vomiting
If your dog drools occasionally and vomits once without any further symptoms, it may not be cause for alarm.
However, here’s what you should do:
Monitor their behavior: Keep an eye on energy levels, appetite, stool consistency, and water intake.
Remove access to food for 6–12 hours: This gives your dog’s stomach time to rest.
Provide small amounts of water: Prevent dehydration but avoid large amounts at once.
After fasting, reintroduce bland food: Boiled chicken and white rice is a safe starting point.
Check for toxins: Look around the house and yard for anything your dog could have eaten.
When to See a Vet Immediately
While many cases of dog drooling before vomiting are mild and resolve on their own, you should call your vet if:
Vomiting persists more than 24 hours
Drooling and vomiting occur frequently
Your dog shows signs of lethargy, fever, or pain
You see blood in the vomit
Your dog is a puppy, senior, or has a chronic illness
There’s a chance of poisoning
Prompt veterinary intervention can prevent complications like dehydration or worsening of a serious condition.
Key Takeaway
Dogs drool before vomiting because their body is preparing to expel something—whether it’s due to nausea, stress, motion sickness, toxins, or illness.
The drooling is a warning sign, and when it’s followed by vomiting, it’s often your dog’s way of saying something’s wrong inside.
While occasional vomiting paired with drooling is not uncommon, frequent or severe symptoms should always be evaluated by a veterinarian.
Knowing the reasons why dogs drool before vomiting helps you take fast action, offer comfort, and get the proper treatment if needed.
By staying alert to these early signs, you can protect your dog’s health and help them recover more quickly.