11 Signs That Your Puppy May Be Sick

1. Lethargy

Your puppy has less energy than usual and seems unusually slow, tired, or disengaged — especially if paired with any of the signs below. This is one of the first indicators that something may be off.

2. Behavior Changes

A normally social puppy who becomes withdrawn, shows reduced interest in play, sleeps more than usual, or seems reluctant to get up could be telling you something is wrong. Sudden aggression or confusion can also signal discomfort or illness.

3. Loss of Appetite

If your puppy suddenly isn't interested in food they normally love, or is unable to eat much of what you offer, these are signs they're not feeling well. Puppies should be enthusiastic eaters.

4. Weight Loss

Unexplained weight loss can point to parasites, metabolic disorders, organ issues, or other conditions that need to be investigated by your veterinarian.

5. Vomiting

Puppy vomiting is never considered normal and should always be addressed promptly. It may signal ingestion of something harmful, a gastrointestinal illness, or other serious concern.

6. Constipation

If your puppy stops pooping entirely, or their stools are hard, small, or contain blood, these are signs of a potential blockage, dehydration, or other issue that warrants veterinary attention.

7. Diarrhea

Loose stool is another red flag. Diarrhea in puppies can quickly lead to dangerous dehydration and can affect nutrition and development. It should never be ignored.

8. Changes in Urination

Increased frequency, straining, discolored urine, or accidents in a previously potty-trained puppy can indicate a urinary tract infection, bladder stones, or other concerns.

9. Respiratory Distress

Discharge from the nose, persistent coughing, sneezing, or open-mouth breathing at rest are all signs of respiratory illness that require veterinary attention.

10. Skin Lesions

Rashes, sores, lumps, or unusual changes in the skin can indicate anything from a minor healing scratch to an infection, allergy, or more serious condition. Common causes in puppies include mites, fleas, fungal infections, allergic reactions, and bacterial infections.

11. Neurological Signs

Discharge from the eyes, thickened paw pads, circling, head tilt, or seizures require immediate veterinary care. These can indicate a serious systemic or neurological problem.

When to Go to the Vet

When a puppy shows any signs of illness, they should be seen by a veterinarian right away.

• Do not wait to see if it resolves on its own. Puppy illnesses that are easily treatable when caught early can become life-threatening if left unaddressed.

• Some diseases, like parvovirus, can deteriorate extremely rapidly in young puppies. If you're ever unsure whether something warrants a vet visit, call and ask. Your vet would always rather hear from you and offer reassurance than have you delay care.

Caring for a Sick Puppy at Home

Always take your sick puppy to the vet for an assessment before attempting to manage symptoms at home. From there, follow your veterinarian's instructions carefully — which may include rest, adequate hydration, a bland diet, and medications prescribed specifically for your puppy.

Pet insurance is worth considering when your puppy is young and healthy. It can make it significantly easier to provide the care your puppy needs without the stress of unexpected costs.

Prevention: Your Best Tool

The single most important thing you can do to protect your puppy's health is ensure they receive their core vaccines on schedule. Please visit our Puppy Vaccine Schedule page in the Health & Wellness section for everything you need to know. Regular deworming, flea and tick prevention (see our Parasite Prevention page), and consistent veterinary check-ups round out a solid preventive care plan.

Know your puppy, trust your instincts, and when in doubt — call your vet. You are your puppy's best advocate.