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How to Tell If Your Puppy Is Sick

Quick answer: Your puppy may be sick if it shows lethargy, loss of appetite, vomiting, diarrhea, coughing, trouble breathing, fever, unusual behavior, or signs of pain. Puppies can get worse quickly, so it is best to act early.

Puppies are energetic, curious, and full of personality, but they can also get sick more easily than adult dogs. Because their bodies are still developing, illness can progress quickly. Knowing the warning signs can help you decide when to monitor closely and when to contact a veterinarian.

Watch for changes in energy

One of the first signs that a puppy may be sick is a change in energy. A normally playful puppy that suddenly becomes lethargic, weak, or unwilling to move may be uncomfortable or unwell. Puppies that seem unusually quiet, sleepy, or reluctant to play may need attention.

It is especially important to take notice if the puppy seems too tired to eat, drink, or stand normally.

Appetite and drinking changes

Loss of appetite is a common sign of illness. A puppy that refuses meals, eats much less than usual, or seems uninterested in food may be sick. Reduced water intake can also be a concern, especially if the puppy seems dehydrated or has been vomiting or having diarrhea.

On the other hand, a puppy that seems very thirsty or is drinking much more than usual may also be unwell. Both extremes are worth watching.

Gastrointestinal symptoms

Vomiting and diarrhea are among the most common signs of puppy illness. They can be caused by diet changes, stress, parasites, stomach upset, or more serious infections. Repeated vomiting, persistent diarrhea, or signs of dehydration should be taken seriously.

Watch for blood in the stool or vomit, severe lethargy, or a puppy that cannot keep food or water down. These may require urgent veterinary care.

Respiratory symptoms

Coughing, sneezing, wheezing, nasal discharge, or trouble breathing can signal a respiratory problem. Puppies may develop infections from other dogs or stressful environments. Mild symptoms can sometimes improve, but persistent symptoms should be evaluated by a veterinarian.

Trouble breathing, blue gums, or extreme fatigue are emergency signs.

Behavior changes

Behavior can change early when a puppy is sick. A puppy may seem more clingy, more withdrawn, less interested in play, or unusually irritable. Some puppies vocalize more, shake, or avoid touch because they feel uncomfortable.

Any sudden change in personality or behavior can be meaningful, especially when it happens alongside other symptoms.

Fever and pain signs

A puppy with a fever may feel warmer than usual, seem unusually tired, or have a reduced appetite. Signs of pain can include panting, whining, guarding a body part, reluctance to move, or sensitivity when touched.

If your puppy seems painful or appears very uncomfortable, contact a veterinarian promptly.

When to call a veterinarian

Contact a veterinarian if your puppy has persistent vomiting, repeated diarrhea, trouble breathing, fever, weakness, severe lethargy, blood in stool or vomit, swollen belly, or signs of severe pain. Puppies can decline quickly, so it is better to seek advice early than to wait and hope things improve.

For related guidance, see Common Puppy Health Problems Every Owner Should Know and How to Keep a Puppy Healthy.

Helpful calculators and related guides

Important: If your puppy seems very sick, weak, or has trouble breathing, seek veterinary care promptly. Young puppies can become seriously ill quickly.

Frequently Asked Questions

How can I tell if my puppy is sick?

Signs include lethargy, appetite loss, vomiting, diarrhea, coughing, trouble breathing, fever, unusual behavior, or pain.

When should I call a vet for my puppy?

Contact a veterinarian if your puppy has persistent symptoms, weakness, trouble breathing, repeated vomiting, severe diarrhea, or seems very uncomfortable.

What are common puppy sickness symptoms?

Common symptoms include poor appetite, diarrhea, vomiting, coughing, sneezing, lethargy, fever, and unusual behavior.