If your energetic dog is suddenly showing signs of reluctance to move or seems unusually tired, it's important to determine the underlying cause. Lethargy, characterized by a lack of energy, can result from fatigue or a potential health issue.

This article explores the various causes, symptoms, and treatments associated with lethargy in dogs, emphasizing the importance of seeking veterinary advice when necessary.

Key Takeaways:

  • Lethargy in dogs is a lack of energy and can be a sign of an underlying health issue.
  • Seek veterinary care for sudden or persistent lethargy, or if other concerning symptoms are present.
  • Treatment depends on the underlying cause and may involve fluid therapy, medication, and other treatments.

What Is Lethargy in Dogs?

Lethargy is specifically a lack of energy in dogs. It is a severe form of canine fatigue, characterized by a loss of interest in usual activities or a reduced activity level in dogs.

Your tired dog may act lethargic when exhausted after energetic activity such as a walk at a dog park or too much playtime, but after your pet rests or has a treat, they should be active and happy again. However, a lethargic dog won't cheer up even at the sight of its favorite treat.

Lethargic dogs are often weak and unwilling to stand, play, or move. They also become anorexic, and nothing seems to make them happy.

Causes of Lethargy in Dogs

Lethargy in dogs can stem from various factors, including infections, nutritional deficiencies, metabolic diseases, medication, or poisoning. Here's a breakdown of each possible cause:


Various kinds of infection, bacterial or viral, can make your dog lethargic. Here are some of them:

Metabolic and organic disease

Several medical conditions can put extra strain on your dog's system, resulting in low energy levels. These include the following:


Your dog might become lethargic after taking newly prescribed drugs or when you use new flea or worm products. It could also be a side effect of a vaccine. Consumption of human medicine, such as ibuprofen, can also cause lethargy in dogs, and should be treated as an emergency situation.


Anemia is a reduction of red blood cells and hemoglobin. It often results from various diseases or an infestation of external or intestinal parasites.

Nutritional deficiencies

Inadequate or low-quality food that has insufficient nutrients for your dog can make them lethargic over time.


Your dog can get toxin ingestion from garlic, leeks, onions, or chocolate.

Other causes include cancer, trauma, pain, hypothyroidism, chronic or acute diarrhea, and snake bite. Mild to severe lethargy can drag your senior dog to a terminal end. Thus, calling your veterinarian immediately for in-home care can help save your pet's life.

Signs & Symptoms of Lethargy in Dogs

Give your veterinarian the correct history of your dog for a quick diagnosis and proper treatment. The following symptoms are the typical signs of lethargy:

  • Canine fatigue: your exhausted dog is acting lethargic as though they have undertaken heavy exercise, despite only carrying out normal activities
  • Listlessness: a loss of interest in everyday activities such as play or walks
  • Reduced activity level: in dogs who have mild to moderate lethargy, you may notice their movement and response to sensory stimulation is slower
  • Behavioral change: your dog may show other behavioral changes, such as exercise intolerance

Since lethargy may arise from numerous conditions, it may be accompanied by other symptoms, such as the following:

Assess all your dog's symptoms, and discuss them with your veterinarian.

When to Seek Veterinary Care

Some symptoms of lethargy might be signs of ailment or other conditions. Since lethargy is not specific to what your pet could be suffering from, it is essential to consult a veterinarian for a proper diagnosis.

Sudden lethargy may indicate severe infection and requires immediate veterinary attention.

If your lethargic dog doesn't show other signs of illness, your veterinarian can advise you to monitor your pet for a few hours. No improvement after 24 hours warrants a physical exam and bloodwork.

You should call for an emergency veterinary visit if you observe one or multiple symptoms in your lethargic dog. Such situations include the following:

Related reading: How Often Should I Take My Dog to the Vet?

Treatment Options for Dogs with Lethargy

Your veterinarian will perform physical examinations on your lethargic dog and inquire about their history. The veterinary doctor will also conduct abdominal, spine, and joint palpation and check gum color and hydration status.

Diagnostic tests such as blood, urine, and fecal tests may be carried out to confirm the underlying problem. The procedure can also include X-rays, imaging scans, echocardiograms, and electrocardiograms (ECG).

Treatment depends on the underlying condition. It may involve fluids for rehydration, antibiotics to cure infections, and pain medicine to relieve pain.

Home Remedies for Lethargic Dogs

Home remedies for dog lethargy include the following:

  • Giving tonic herbs which are antioxidants and energizers (such as rosemary)
  • Vitamin B — good sources are organ meats and raw milk (unprocessed)
  • Digestive enzymes to aid in digestion and nutrient absorption

Some could be chronic or life-threatening, so it's essential to obtain your veterinarian's recommendation before using home remedies on your lethargic dog.


Dog lethargy is a nonspecific sign that could manifest from various underlying causes. These may include infections, metabolic diseases, anemia, pain, or nutritional deficiencies. Since only a veterinarian can correctly diagnose your ailing pet, you should seek professional help when your dog becomes lethargic. 

Frequently Asked Questions

Can allergies cause lethargy in dogs?

A dog's allergies cannot directly cause lethargy unless they scratch themselves too much, resulting in wounds. Allergies of the digestive system can result in vomiting and diarrhea, predisposing your dog to lethargy.

Can antibiotics cause lethargy in dogs?

Yes, they can have various side effects, such as nausea and loss of appetite, causing lethargy in the long run.

Can dog ear infections cause lethargy?

Ear infections can be excruciating, and the pain can make your dog lethargic. Such conditions require emergency veterinary intervention.

Can worms cause lethargy in dogs?

In large numbers, worms can cause dog lethargy, as these parasites are often associated with anemia.