A dog that is vomiting, has diarrhea, or has a fever loses fluid faster than usual, and illness often makes dogs less interested in drinking. That combination is why dehydration is one of the main worries when a dog is unwell. This guide covers gentle ways to encourage fluids at home, and when home care is no longer enough.
For everyday hydration tips for healthy dogs, see how to hydrate a dog and keep them hydrated.
Why hydration matters more when a dog is sick
Water helps the body regulate temperature, circulate blood, and move nutrients and waste. When a sick dog loses more fluid than they take in, the situation can worsen quickly, especially in puppies, small dogs, and seniors. Dehydration can also make nausea and tiredness worse, which makes a dog even less likely to drink.
Signs of dehydration
Look for:
- Dry, sticky, or tacky gums
- Lethargy or unusual weakness
- Sunken eyes
- Skin that is slow to return to place when gently lifted at the back of the neck
- Thick saliva and heavy panting
- Little or no urine, or very dark urine
These checks are not perfectly reliable, and a dog can be dehydrated without all of them. If your dog is sick and you notice more than one of these, contact a vet.
Ways to encourage drinking
Start with the basics:
- Keep fresh, clean water where your dog rests, so they do not have to move far.
- Try a different bowl, or move the bowl closer.
- Offer ice chips or ice cubes to lick. Some dogs accept these when they refuse a bowl.
- Offer water after they have rested, not right after vomiting.
Small, frequent sips
A very thirsty dog that gulps a large amount may vomit it back up. Offering small amounts more often tends to be gentler on a sensitive stomach. If your dog has been vomiting, ask your vet how soon after the last episode to offer water and how much. If water comes straight back up, that is a sign to call a vet.
Flavoring water safely
A little flavor can make water more tempting. Options people commonly use include:
- A splash of plain, unseasoned, low-sodium broth (chicken or beef)
- Water from plain canned tuna packed in water, in small amounts
Always check labels. Many human broths include onion, garlic, high salt, or other additives that are harmful to dogs. Our guide to beef broth for dogs has label tips. Keep flavoring light, since too much salt or richness can upset the stomach.
Wet food, or kibble soaked in warm water, can also add fluid. See food for sick dogs for gentle feeding ideas.
Using a syringe or dropper
Some vets and rescue groups suggest using a clean oral syringe or dropper to give tiny amounts of water into the cheek pouch of a dog that will not drink. This carries risks. If liquid goes toward the back of the throat or the dog’s head is tilted back, it can be inhaled into the lungs. If you want to try it, ask your vet or clinic to show you how, and go slowly, a little at a time, letting the dog swallow between squirts. Stop if your dog coughs, gags, or struggles.
What to avoid
- Forcing large amounts of water into a dog.
- Sports drinks and electrolyte products made for people, which can contain sugar or sweeteners unsuitable for dogs. Ask your vet if an electrolyte solution is appropriate.
- Milk, which many dogs do not digest well.
- Human medications to stop vomiting or diarrhea. Check with your vet first.
How quickly can a sick dog rehydrate?
It depends on how much fluid has been lost and why. A mildly dehydrated dog who starts drinking again may improve within hours. A dog who has lost a lot of fluid, or who keeps vomiting, often needs veterinary treatment such as fluids given under the skin or through a vein, which can restore hydration far more quickly and safely than drinking alone. Be wary of trying to “fix it fast” at home.
When home care is not enough
Contact a vet promptly if your dog:
- Will not drink for a day, or cannot keep water down
- Is vomiting repeatedly, or has ongoing diarrhea
- Has pale, dry gums, sunken eyes, or seems weak or collapsed
- Is a puppy, senior, or has a condition like kidney disease or diabetes
- Is also not eating, or seems to be in pain
Dehydration can be serious, and a vet can find and treat the cause. For wider advice on looking after a dog who is unwell, see our guide to caring for a sick dog.