Dog Diarrhoea: Causes, Home Care and When to Worry

A bout of diarrhoea is one of the most common reasons owners worry about their dog — and one of the most common things to clean up off the kitchen floor at 6am. The reassuring news is that most cases are mild and settle within a day or two. But some need a vet, so here's how to tell the difference and care for your dog in the meantime.

This is general guidance, not a substitute for veterinary advice — if you're worried about your dog, contact your vet.

What diarrhoea is

Diarrhoea simply means loose or watery stools, often more frequent and more urgent than usual. It's a symptom rather than a disease — your dog's gut reacting to something and trying to clear it out. Short-lived diarrhoea in an otherwise bright, well dog who is still eating and drinking is usually nothing to panic about.

Common causes

The usual suspects include:

• Dietary indiscretion — eating something they shouldn't, from bin raids to scavenged scraps on a walk.
• A sudden change of food — switching diets too quickly upsets many dogs' tummies.
• Stress or excitement — a new home, kennels, travel or even a big day out.
• Infections and parasites — including worms.
• Food intolerances or sensitivities.

More persistent or recurring diarrhoea can point to underlying conditions that need investigating by your vet.

Signs and symptoms

Beyond the loose stools themselves, the most useful thing is to notice how your dog is in themselves. Are they bright, bouncy and eating, or quiet, flat and off their food? Note the colour and consistency, whether there's any blood or jelly-like mucus, how often it's happening, and whether vomiting is happening alongside it. All of this is genuinely helpful information for your vet.

What you can do at home

For a mild case in an otherwise well adult dog:

• Make sure fresh water is always available — diarrhoea causes fluid loss and can lead to dehydration.
• Many vets suggest a bland, easily digestible diet for a day or two, such as a vet-recommended sensitivity food. Avoid sudden diet changes and rich treats while the tummy settles.
• Reintroduce their normal food gradually once stools firm up, mixing it in over a few days.
• Don't withhold food from puppies, and don't fast adult dogs for long periods without veterinary advice — current guidance has moved away from prolonged starvation.
• Use our can my pet eat this tool to rule out anything they shouldn't have eaten.

Keeping worming up to date prevents a common cause — see how often to worm a dog — and you'll find sensitive-tummy foods and supplies in our shop.

How to prevent tummy upsets

Many bouts of diarrhoea are avoidable with a few sensible habits. Change your dog's food gradually whenever you switch — mixing increasing amounts of the new food with the old over about a week gives the gut time to adjust, rather than the sudden swap that catches so many dogs out. Resist the urge to share rich human food, fatty scraps and table leftovers, which are a frequent trigger. On walks, discourage scavenging and bin-raiding, as eating something off the ground is one of the most common causes of all. Keep worming and parasite control up to date, store food properly so it doesn't spoil, and introduce new treats one at a time so you can spot anything that doesn't agree with your dog. If your dog has a sensitive stomach by nature, a consistent, good-quality diet without constant chopping and changing usually keeps things much steadier. None of this guarantees a cast-iron tummy, but it dramatically cuts down the 6am surprises.

When to see a vet

Contact your vet promptly if:

• There's blood in the diarrhoea, or it's black and tarry (which can indicate bleeding higher up the gut).
• Your dog is also vomiting repeatedly, lethargic, or has a painful or bloated tummy.
• The diarrhoea lasts more than 48 hours, or keeps recurring over weeks.
• Your dog is a puppy, elderly, or has another health condition — these dogs dehydrate faster and need quicker action.
• You suspect they've eaten something toxic or a foreign object such as a toy or sock.
• Your dog seems generally unwell, weak, or won't drink.

Persistent or severe diarrhoea can cause dehydration, so don't leave it too long. Find a vet via our vets directory. If vomiting is also involved, our why is my dog being sick guide will help, and recurring tummy issues sometimes link to dog allergies.

The takeaway

Most diarrhoea is a passing nuisance rather than a crisis, and a well dog who's still bright and eating will usually be back to normal within a day or two with water, rest and a bland diet. The important thing is to keep watching how your dog is in themselves and to act quickly on the red flags — blood, repeated vomiting, lethargy, a painful tummy, or a poorly puppy or senior. Trust your instincts: if something feels more serious than a simple upset tummy, ring your vet.

Sources

• PDSA — Pet Health Advice
• Blue Cross — Pet Advice
• RSPCA — Dogs