How to rehydrate a dog

Fluid replacement helps maintain the hydration, electrolyte balance and overall health of dogs. This is particularly important if they’re ill, injured or otherwise dehydrated.

Like humans, dogs rely on adequate hydration to support vital functions such as circulation, digestion and temperature regulation. If a dog loses excessive fluids due to vomiting, diarrhoea or heatstroke, for example, fluid replacement may become necessary.

Here we look at when you may need to replace your dog’s fluids, a recipe to do so, and how to administer it.

Another way to take care of your furry friend is to make sure they have peace-of-mind dog insurance.

Why is fluid so important?

First of all, replacing fluids is important for maintaining hydration. Water makes up about 60-70% of a dog’s body weight, and maintaining hydration is crucial for organ function, absorbing nutrients and eliminating waste.

When dogs lose fluids and aren’t able to replace them by drinking water, they can become dehydrated, which can lead to impaired kidney function, reduced blood circulation, and – in severe cases – organ failure.

Secondly, it’s important for the balance of electrolytes. Fluids which contain electrolytes such as sodium, potassium and chloride are essential for things like muscle function and regulating pH balance. If a dog vomits or has diarrhoea, they not only lose water but also these critical electrolytes. Imbalance can lead to symptoms such as muscle weakness and lethargy.

It’s also important for preventing hypovolemic shock. This is where the heart isn’t able to pump enough oxygen around the body. Administering fluids helps restore blood volume and stabilise the dog’s condition.

Before you do anything

Please note that it’s a good idea to contact your vet before you start rehydrating your dog yourself. If a dog needs fluid replacement instead of regular water, there’s a chance they may be so unwell that they need to be put on a drip directly into the blood.

How to make fluid replacement

It’s possible to buy oral rehydration solutions (ORS), which contain a mix of water, electrolytes and glucose. Alternatively you can make your own fluid replacement for your dog by mixing water, dextrose and salt.

Boil the water so that the liquid substitute is mixed well. Be sure to let the replacement cool down properly before giving it to your dog. The replacement must be stored in a refrigerator and will stay fresh for up to 24 hours. Then you need to make a new fluid replacement.

Recipe for fluid replacement for dogs

• 1 litre of water
• 1 tablespoon dextrose or honey
• 1 teaspoon of salt

A dog normally needs around 0.5 decilitres (50ml) of fluid per kilogram of body weight per day. So, for a 10kg dog, they’ll need 500ml. In case of fluid loss, the dog may need twice as much.

How you give your dog fluid replacement

At first, you may need to ‘feed’ the dog with the help of a spoon or syringe. This is done most easily via the corner of the mouth. Portion out the fluid replacement that you give your dog, and go steady. Excessive and rapid fluid intake can lead to vomiting.

This method is appropriate for dogs that are still able to drink on their own and are not experiencing severe vomiting or weakness.

If your dog is unable to take fluids orally, or they have severe vomiting or diarrhoea, you’ll have to take them to the vet. They will either administer fluids subcutaneously (under the skin) if the dehydration is mild to moderate, or intravenously in more severe cases.

To find out more about your dog’s health, check out our diet and nutrition guides for dogs, and also a list of substances which are toxic to dogs.

Last reviewed by Owe Carter on 14 September 2024.