If your dog is shivering, not eating, and lethargic, it’s time to pay attention.
These three symptoms together are red flags that something serious may be happening.
While each one alone can sometimes be brushed off—shivering from cold, skipping a meal, or a lazy day—when they appear together, they can point to illness, pain, or systemic imbalance that shouldn’t be ignored.
We break down why this happens, what it could mean, and when to call your vet. We’ll also help you figure out what to do at home in the meantime.
Dog Shivering, Not Eating and Lethargic: Why It Happens
A dog that is shivering, not eating, and lethargic is likely experiencing an underlying medical issue that impacts energy, comfort, and appetite.
Common causes include infection, pain, poisoning, digestive problems, organ disease, or emotional stress.
These symptoms often appear together because they reflect internal dysfunction or physical discomfort.
Lethargy often follows appetite loss, while shivering may signal pain, fever, or distress.
Common Reasons Why Your Dog Is Shivering, Not Eating, and Lethargic
1. Viral or Bacterial Infections
Infections like parvovirus, leptospirosis, or kennel cough can cause dogs to feel weak, lose interest in food, and tremble from fever or nausea.
These are especially dangerous for puppies and unvaccinated dogs.
Shivering may be one of the earliest signs, followed by lethargy and appetite loss.
Other possible symptoms include vomiting, diarrhea, coughing, or nasal discharge.
Related: Dog shivering and not eating (Causes and what to do)
2. Poisoning or Toxin Exposure
Toxins—like pesticides, human medications, spoiled food, or household cleaners—can cause rapid and severe reactions in dogs.
Shivering may result from muscle tremors, while lethargy and not eating stem from systemic damage or gastrointestinal distress.
If your dog suddenly becomes lethargic, won’t eat, and trembles, especially after being outdoors or left unsupervised, poisoning should be high on your list of concerns.
3. Pain or Internal Injury
Dogs in pain often go quiet and withdrawn. If your dog is shivering and lethargic and won’t eat, they may have sustained an injury (internally or externally).
Conditions like pancreatitis, back pain, or abdominal trauma can cause this triad of symptoms.
Senior dogs are especially vulnerable—if your old dog is shivering and not eating, and also acting lethargic, underlying joint or nerve pain may be involved.
4. Fever or Hypothermia
Shivering is a classic sign of fever—or, conversely, of being too cold.
If your dog’s body temperature is too high or too low, they may become inactive and lose interest in food.
This may follow infection or exposure to cold weather.
Feel their ears and paws—if they’re hot, your dog may have a fever; if cold, your dog may be hypothermic.
Either situation can cause lethargy and appetite suppression.
Related: Senior dog shivering and not eating but drinking water (Here’s why)
5. Gastrointestinal Problems
Digestive issues like nausea, gastritis, or intestinal blockage can cause a dog to feel miserable.
Shivering may be their way of coping with discomfort, and they may stop eating altogether.
Lethargy soon follows when their energy levels drop due to lack of nutrients or hydration.
If your dog also vomits or has diarrhea, this points even more strongly to a gastrointestinal issue.
6. Stress or Anxiety
Stress can manifest physically in dogs.
A stressed dog may tremble, avoid food, and retreat into a quiet, sluggish state.
Emotional stress from a loud environment, a change in routine, or separation anxiety can drain a dog mentally and physically.
This is more common in puppies and small breeds, who may also be more sensitive to environmental stressors.
7. Chronic Illness or Disease
Conditions like kidney disease, liver failure, or heart disease often start subtly—with shivering, fatigue, and a decreased appetite.
If your dog has had recent blood work showing abnormal values, or if they’re older and showing vague signs of illness, these conditions should be considered.
In these cases, a dog may still drink water, but the combination of shivering, lethargy, and not eating means their system is under stress.
How Serious Is It?
When these three symptoms—shivering, appetite loss, and lethargy—appear together, it’s almost always a medical concern.
This is especially urgent if:
The symptoms appear suddenly
Your dog is a puppy or senior
You notice other symptoms like vomiting, diarrhea, or pale gums
Your dog hasn’t eaten for 24+ hours
The lethargy is severe (they won’t move or get up)
Early veterinary evaluation can prevent complications and improve outcomes.
What to Do if Your Dog is Shivering, Not Eating, and Lethargic
1. Take Their Temperature
A dog’s normal body temperature is between 101°F and 102.5°F (38.3°C–39.2°C). Anything above or below this range should be considered abnormal.
Use a pet thermometer and call your vet with the reading.
A fever may suggest infection, while a low temp could indicate hypothermia or shock.
2. Keep Them Warm and Quiet
Regardless of the cause, keeping your dog in a warm, comfortable space helps ease stress and shivering.
Avoid loud environments or unnecessary handling. Offer a cozy blanket and ensure their area is draft-free.
3. Check for Poison Risks
If you suspect toxin ingestion (chewed pills, cleaners, unknown food, insect bait), bring your dog to the vet immediately.
Bring any labels or packaging with you. Time is critical with poisons.
4. Offer Easy-to-Digest Food
If your dog hasn’t eaten in 12–24 hours, try a small serving of bland food—boiled chicken and rice is a common choice.
Avoid fatty or seasoned food. If they refuse it or vomit after eating, call your vet.
5. Monitor Other Symptoms
Keep a close eye on vomiting, diarrhea, urination, breathing, gum color, and behavior changes.
These can help your veterinarian identify the root cause faster and more accurately.
6. Call Your Veterinarian
If your dog continues to shiver, remain lethargic, and avoid food—even if they’re drinking—it’s time to get medical help.
Blood tests, imaging, and physical exams can detect what’s wrong.
Your vet may provide fluids, anti-nausea meds, or further testing depending on the case.
Related: Dog shivering and not eating and vomiting
Key Takeaway
Shivering, not eating, and lethargy in dogs are not symptoms to ignore—especially when they happen together.
These signs point to physical discomfort, disease, or emotional stress that can escalate quickly if left unaddressed.
Whether the cause is a minor illness or something more serious, early intervention is your dog’s best shot at a full and swift recovery.
If your dog continues to show these symptoms for more than 12–24 hours, don’t wait.
Call your veterinarian and get to the bottom of it. You know your dog best—when something feels off, trust your instincts.