My Dog is Drooling and Lethargic (Here’s What You Need To Know)

1. Heatstroke

One of the most dangerous causes of excessive drooling and lethargy in dogs is heatstroke.

This condition occurs when a dog’s body overheats and can’t cool itself down fast enough.

Symptoms of heatstroke in dogs include:

• Heavy panting

• Bright red gums

• Excessive drooling

• Vomiting or diarrhea

• Weakness or collapse

• Lethargy or unresponsiveness

Heatstroke is a medical emergency. Brachycephalic breeds (like Bulldogs or Pugs) and dogs left in hot environments are especially prone.

Move your dog to a cool place, offer water, and seek immediate veterinary care.

Related: Dog drooling and shaking head (Explained)

2. Nausea or Upset Stomach

Nausea is a frequent reason for drooling in dogs. When dogs feel nauseous, they tend to salivate more and may become sluggish or reluctant to move.

Common causes of nausea include:

• Motion sickness

• Dietary indiscretion (eating something they shouldn’t)

• Gastrointestinal infections

• Pancreatitis

A dog that is drooling and lethargic with an upset stomach may also show signs of:

• Lip smacking

• Vomiting or gagging

• Loss of appetite

• Pacing or restlessness

If nausea lasts more than a few hours or is accompanied by vomiting or diarrhea, contact your vet.

3. Poisoning or Toxin Exposure

One of the most alarming causes of a dog being drooly and lethargic is poisoning. Dogs may ingest toxins such as:

• Chocolate

• Grapes or raisins

• Human medications

• Household cleaners

• Pesticides or rat poison

Toxins can rapidly affect a dog’s digestive, neurological, or cardiovascular systems.

Signs of poisoning in dogs include:

• Sudden excessive drooling

• Vomiting or diarrhea

• Tremors or seizures

• Pale gums

• Weakness or collapse

If you suspect poisoning, don’t wait—call your veterinarian or an emergency animal poison hotline immediately.

Related: Dog Drooling and Runny Nose (Explained)

4. Oral Injuries or Dental Problems

Dental diseases like gum infections, broken teeth, or foreign objects stuck in the mouth can lead to dog drooling excessively and acting lethargic.

Oral pain can affect your dog’s appetite and behavior.

Other signs of dental issues include:

• Swollen face or jaw

• Dropping food from the mouth

• Pawing at the mouth

• Bad breath

If your dog is drooling with a swollen mouth and low energy, an oral exam is necessary.

5. Infections and Fever

Systemic infections—bacterial, viral, or fungal—can make your dog feel drained and sick, which explains why a dog becomes lethargic and drools more than usual.

Fever associated with infections may increase panting and salivation, particularly if the throat, respiratory system, or mouth is involved.

Look out for:

• Shivering or trembling

• Dehydration

• Loss of appetite

• Swollen lymph nodes

Veterinary tests like bloodwork or imaging may be required to diagnose and treat the infection.

6. Liver or Kidney Disease

Chronic conditions like liver or kidney failure often result in lethargy and drooling in dogs as waste products build up in the blood and make them feel nauseous or unwell.

Symptoms to watch for:

• Bad breath (especially ammonia-like)

• Vomiting

• Increased thirst and urination

• Yellowing of eyes or gums (jaundice)

• Sudden weight loss

If your dog has persistent drooling and is sluggish, it’s vital to check organ function through veterinary lab work.

7. Neurological Disorders

Conditions like seizures or neurological disease can manifest subtly in the early stages as drooling and lethargy in dogs.

Signs of neurological problems include:

• Disorientation

• Circling

• Head tilting

• Involuntary drooling

• Lack of coordination

Any behavioral or physical changes, especially paired with sluggishness and excessive drooling, should be addressed by a vet immediately.

8. Bloat or Gastric Dilatation-Volvulus (GDV)

GDV, also called bloat, is a life-threatening condition where the stomach fills with gas and may twist.

It’s more common in large, deep-chested breeds like Great Danes or German Shepherds.

Key symptoms:

• Excessive drooling

• Lethargy or collapse

• Unproductive retching

• Distended or hard abdomen

• Pacing and discomfort

If your dog is drooling and weak with a swollen belly, this is a veterinary emergency.

When to See a Vet if Your Dog Is Drooling and Lethargic

While some causes of dog drooling and being lethargic are minor or temporary, others are urgent.

Seek immediate vet care if your dog:

• Is drooling excessively for more than a few hours

• Shows signs of vomiting, diarrhea, or collapse

• Appears disoriented or is unresponsive

• Has swollen or painful areas

• Stops eating or drinking for over 24 hours

• May have been exposed to toxins

Your vet will assess vital signs, perform diagnostics like bloodwork or imaging, and determine the best course of treatment.

What You Can Do at Home

If the symptoms are mild and your dog seems otherwise okay:

• Offer fresh water and encourage hydration

• Remove access to any potential toxins or foreign objects

• Observe for signs of worsening condition

• Check your dog’s mouth for any foreign bodies or injuries

Avoid giving any human medications or home remedies unless instructed by a veterinarian.

Key Takeaway: Why Dog Drooling and Lethargy Happen

When your dog is drooling and lethargic, it’s more than just an off day.

These symptoms can be the first signs of serious health problems like poisoning, heatstroke, organ disease, or infections.

The key is to monitor your dog closely and act fast if symptoms worsen.

While some cases of dog lethargy and drooling may resolve on their own, others can become life-threatening without proper veterinary care.

By staying informed and alert to changes in your dog’s behavior, you can protect their health and well-being.