Mythbuster: Owners should stop feeding a cat or dog that is vomiting or has diarrhoea

Irina Wells
23 March 2021 - 2 min read

Dr Sophie Bell, a veterinary surgeon, looks into another myth for our mythbuster series. Should owners starve a cat or dog when they are vomiting or have diarrhoea?


Both vomiting and diarrhoea can be caused by many things – bacteria, viruses, parasites, dietary change, allergies, or a blockage such as a stone. Any ongoing vomiting and diarrhoea will need veterinary investigation, but what action can you take to help your dog or cat?

Past advice was to starve pets overnight or up to 24 hours if they had an upset tummy. The theory behind this was to allow the digestive tract time to settle and recover. However, starving can create major problems for our pets.

Problems with starving a pet when sick

  • They absorb some water from food, which can help slow the progression of dehydration

  • They need energy and nutrients from food to help them recover

  • With cats, starvation can increase the risk of the development of fatty liver syndrome

When our pets have an upset tummy, they can lose vast amounts of fluid leading to dehydration. They may increase their fluid intake by drinking more, along with using moisture from food to try and compensate.

If the illness is ongoing or very severe, signs of dehydration may be seen and increased drinking will not help to resolve it. They would need a hospital stay with the administration of intravenous fluids.

Withholding food can increase the risk of dehydration developing faster and may make the pet feel weak.

How to help a pet with an upset stomach

It is important to choose bland foods.

This is likely to be something different from their usual diet. And it's a good idea to feed small meals frequently throughout the day. For small dogs and cats, it may be as little as a spoonful of food 6 times a day. This allows them to receive vital nutrition but does not overload the gut like a large meal potentially could.

Choosing a good source of fibre to help with firming a loose stool is important.

This could be canned pumpkin, cooked and mashed sweet potato or butternut squash. The added bulk fibre can help regulate the bowel. Rice and pasta are often recommended, and can provide some energy and are bland, but I believe choosing a high-fibre substitute is more effective.

Chicken to help your pets upset tummy?

Chicken is often chosen as a bland protein source for dogs and cats. But allergies associated with feeding chicken are on the rise and frequently reported. The risk of exasperating the vomiting and diarrhoea when fed to pets who have not been exposed to it in the past is a risk.

I have seen dogs with diarrhoea become more ill when fed boiled chicken to aid recovery. I usually opt for either white fish or scrambled eggs as a good protein source. Remember, keep it plain, so no milk or butter added to the eggs.

Offering bland food, plenty of fresh drinking water, and giving small but frequent meals can really help. But do not forget, if your pet is showing signs such as a refusal to eat, lethargy, blood in the diarrhoea, and/or vomit, or if they have another underlying condition such as diabetes, always contact your vet for advice.

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