If a dog loses excessive fluids due to vomiting, diarrhoea or heatstroke, for example, fluid replacement may become necessary. Administering fluids helps restore blood volume and stabilise the dog’s condition. It’s possible to buy oral rehydration solutions, 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. 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 of fluid per kilogram of body weight per day. 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. 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 if the dehydration is mild to moderate, or intravenously in more severe cases.