Diarrhoea in Dogs: When to Worry

By Dr Eloise Bright 6 Min Read

For dog owners diarrhoea can be a relatively frequent occurrence and knowing when to worry, when to treat at home and what to look for can be important. We run through what you need to know.

For many diseases diarrhoea may be the only warning sign and some early intervention can save your pet discomfort and save you from a complete smelly mess. In these cases early treatment can actually save you money. On the other hand, rushing your pet to the vet every time you see some soft faeces is not practical or necessary.


  • Diarrhoea that is very watery that has been going on more than 48 hours (can lead to dehydration).
  • Diarrohea with vomiting, lethargy and loss of appetite.
  • Abdominal pain -sitting in the praying position with abdomen stretched out, panting excessively, vocalising when touched or pacing.
  • Bloated or obviously distended abdomen.
  • Black faeces – can indicate digested blood.
  • Large amounts of fresh blood (a small amount just once is okay).


If your dog is bright and happy, the diarrhoea has been going on for less than 48 hours and none of the above has occurred, you probably don’t need to worry…yet. It is quite likely your dog has just eaten something that has upset his gastrointestinal tract, whether it be a rich food, something fatty or perhaps something a bit stinky at the park.


  1. Avoid giving any human medications to your pet without veterinary advice. Many medications have a different effect on dogs compared to humans, so it is best to err on the side of caution. For dogs that are well (and not very old or very young), the best thing you can do is fast your dog for 24 hours. Do not feed anything at all, just water. If your dog is vomiting, is old and debilitated or is a young toy breed, perhaps ask for veterinary advice first before doing the fast.
  2. After the 24 hour fast, hopefully your dog has stopped defecating quite so much and things are settling down. At this point it is likely the intestines need some recovery time. Feeding a bland diet of cooked lean chicken and white rice in a 50:50 ratio is easy to digest and gentle. Feed this for 5 days, then gradually introduce your dog’s normal food over a further 7 days. Sudden diet changes are usually not great for dogs. Your dog may also need some probiotics to repopulate the gut flora appropriately. Avoid the use of yoghurt in pets, as the ‘good’ bacteria would not survive the trip from the stomach anyway. You are better off with a proper dog formulation.


If your dog has intermittent diarrhoea that has been going on for weeks, not just days, visit your vet. For the price of a consultation fee, they can provide some advice on what to feed and advise you as to whether any further tests are required, or if money is short often a treatment trial is recommended.

Bringing in a relatively fresh faecal sample is also a great idea and at least saves you having to describe what the diarrhoea looks like. Your vet will also want to know how frequently your pet is defecating, whether there is blood or mucus, whether there is straining and what you feed your dog.

Your pet may have a simple food intolerance or allergy, in which case the bland diet may work or a low allergen food (like Hills Z/D or Royal Canin Hypoallergenic). There may of course be something more serious going on, like a pancreatic problem or infection, so the sooner you get a diagnosis the happier everyone will be.


Remember that some of the causes of diarrhoea like coccidia, giardia and E.coli are infectious to humans to. Make sure you wash your hands after cleaning up any messes, after handling your dog and before eating. Any surfaces can be cleaned with a 20% bleach solution and for carpets, using an enzymatic cleaner is more effective for biological smells and stains.

The above discussion about diarrhoea is intended to help you decide whether your pet needs immediate veterinary attention and is not a substitute for a proper medical consultation. If your pet is lethargic or unwell, please ring your vet for advice, or ring one of the after-hours emergency centres in your area.

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Dr Eloise is a Clinical Lead at Love That Pet and one of our resident pet care experts. She also curates the select range of vet recommended and approved products which feature on our site.
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