How to tell if your dog is sick
The signs of fever, dehydration, poisoning and parvo, and when not to wait. This guide doesn't replace a vet: if in doubt, call one.
Reviewed by Paola De Valeri, veterinarian, October 17, 2026.
Go to the emergency vet right away if…
- It struggles to breathe, or its gums look pale, gray or bluish.
- It has seizures, can't get up or seems disoriented.
- It vomits or has diarrhea with blood, especially a puppy.
- Its belly is swollen and hard, and it retches without being able to vomit.
- It ate poison, human medicine, chocolate or something with xylitol.
- It was hit by a car, fell from a height or took a hard blow, even if it looks fine.
- Its temperature reaches 41 °C (105.8 °F) or more: it may have a seizure.
Call before you leave so they expect you. For Mexico City we keep a list of 24-hour animal hospitals.
If your dog has a seizure
- 1. Don't pick it up or move it. While seizing, it can bite you without meaning to. Move away anything that could hurt it, but not the dog.
- 2. Wait for it to end. Leave it on the floor for a few minutes: at first it may not recognize you.
- 3. Talk to it and wait for it to respond. Once it responds well to your voice and cues, take it to the emergency vet or call your vet.
24-hour animal hospitals
24-hour vets in Mexico City
Phone numbers and directions for hospitals with 24-hour emergency care, by borough (page in Spanish).
How to tell if it has a fever
- A dog's normal temperature is 38 to 39.2 °C (100.4 to 102.6 °F).
- The only reliable way to measure it is a digital rectal thermometer with a little petroleum jelly. A dry or warm nose doesn't mean fever.
- Over 39.5 °C (103.1 °F), or a fever that lasts more than a day: call your vet.
- 41 °C (105.8 °F) or more: it's an emergency and it may have a seizure.
- Other signs: lethargy, not wanting to eat, shivering or panting without exercise.
How to tell if it's dehydrated
- Dry or sticky gums instead of moist ones.
- If you gently lift the skin on its back, it's slow to fall back into place.
- Sunken eyes, lethargy and very little urine.
- It's more common with heat, vomiting or diarrhea: offer fresh water little by little and, if it doesn't improve or keeps vomiting, take it to the vet.
If you think it's been poisoned
- Signs: vomiting, heavy drooling, tremors, diarrhea, stumbling or seizures.
- Don't make it vomit or give home remedies (milk, oil, salt): they can make it worse.
- Take it to the vet right away and bring the package or a little of what it ate.
Signs of parvo in puppies
- Vomiting, diarrhea (often bloody and foul-smelling), lethargy and not wanting to eat.
- It mostly affects puppies that haven't finished their vaccines.
- It's highly contagious and can be fatal within days: see the vet as soon as you notice these signs and keep it away from other dogs.
- The best prevention is getting its vaccines on time.
Frequently asked questions
- How can I tell if my dog has a fever without a thermometer?
- There's no reliable way: a dry nose or warm ears don't mean fever. If you notice lethargy, it won't eat or it's shivering, take its temperature with a digital thermometer or call your vet.
- What is a dog's normal temperature?
- Between 38 and 39.2 °C (100.4 to 102.6 °F). Over 39.5 °C (103.1 °F) is a fever, and 41 °C (105.8 °F) or more is an emergency: it may have a seizure.
- What do I do if my dog has been poisoned?
- Don't make it vomit or give home remedies. Take it to the vet right away and bring the package of what it ate.
- How can I tell if my puppy has parvo?
- The most common signs are vomiting, bloody diarrhea, lethargy and loss of appetite, especially if its vaccines aren't complete. It's an emergency: take it to the vet right away.
Related guides
- Dog and cat vaccines in Mexico: schedule and vaccine recordWhich vaccines dogs and cats need in Mexico, the rabies rule and how the vaccine record (cartilla) works.
- How often to deworm a dog or a catHow often to deworm a dog or cat by age, and signs that it has parasites.
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Sources
Information from: