Dog diarrhoea: what to do at home, and when it’s time to see the vet

Something from the bin, a new food, a stressful day at the kennels: most bouts of diarrhoea in dogs clear up in a day or two. The job is to spot the few that don’t, and to keep your dog drinking in the meantime.

By Jérôme Mascarin, dog trainer and founder of Canibest updated 11 November 2026

Beagle asleep on a cushion, dog diarrhoea — Photo: Trougnouf (Benoit Brummer), CC BY 4.0, via Wikimedia Commons, cropped and titled by Canibest

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See a vet the same day if there is blood (red or black, tarry poo), if your dog is also being sick, seems flat or in pain, won’t drink, or if it’s a young puppy, an elderly dog or a dog with a health condition. Watery diarrhoea in a puppy can mean parvovirus, especially if it isn’t fully vaccinated.

The usual suspects

scavenging: bins, picnics, dead things on the beach
a sudden change of food, or too many treats
stress: kennels, moving house, fireworks
worms and other parasites
infections (bacteria, viruses)
less often: food intolerance, pancreatitis, inflammatory bowel disease

At home: the first 48 hours

For an adult dog that is bright, eating and has no warning signs:

Water, always. Fresh water available at all times. Dehydration is the main risk.

Small, bland meals. Several small portions a day of something easy to digest, such as boiled skinless chicken with plain rice, or a vet-recommended gut diet. Then mix back into the usual food over a few days.

No human medicines unless your vet prescribes them. Several are toxic to dogs.

If it isn’t clearly improving after 24 to 48 hours, book an appointment.

Signs that it can’t wait

blood in the poo, or black, tarry poo
vomiting at the same time
lethargy, a tense or painful tummy, pale gums
not drinking, or signs of dehydration (dry gums, skin that stays tented when pinched)
diarrhoea lasting more than two days, or coming and going for weeks
your dog may have eaten something toxic or a foreign object

A photo of the poo and a note of what your dog might have eaten help the vet a lot.

Preventing the next one

Change foods gradually over about a week, keep bins dog-proof, worm regularly as advised by your vet, and keep vaccinations up to date. A dog that hoovers everything on walks may benefit from a basket muzzle and some “leave it” training.

Diarrhoea: what owners ask

Should I starve my dog with diarrhoea?

Vets now usually prefer small, frequent bland meals rather than a long fast. Never take water away.

My dog has diarrhoea but is acting normal. Is that OK?

Often yes for a day or so. Keep them drinking, feed bland, and call the vet if it lasts beyond 48 hours or any warning sign appears.

Can I give my dog probiotics?

Dog-specific probiotic pastes can help some dogs. Ask your vet which one, and don’t use them instead of a check-up when warning signs are present.

Sources: PDSA, diarrhoea in dogs, MSD Veterinary Manual, digestive disorders of dogs