What causes diarrhoea in dogs and puppies?

Diarrhoea (often spelt diarrhea*) are stools that are soft to liquid in consistency. Dog diarrhoea is a common problem, largely because dogs will put almost anything in their mouths. Most cases of diarrhoea in dogs are not serious and will resolve themselves. The most likely cause of dog diarrhoea is scavenging — eating things such as table leftovers — or sudden changes in diet.

Other chronic causes of dog diarrhoea can include food allergies and intolerances.

However, it’s worth bearing in mind that diarrhoea in dogs may be the result of a more serious condition such as an infection, parasites, swallowing a foreign body or a poisonous substance. Infections with common viruses such as parvovirus, and coronavirus may also trigger it.

How to treat diarrhoea in dogs and puppies

If the diarrhoea is accompanied by other signs such as severe vomiting, loss of appetite or lethargy please consult your vet or, out of hours, your nearest Vets Now pet emergency service. If this isn’t the case try following these guidelines:

If your dog is not vomiting:

Remove all food and limit your dog to water for 12 hours.  Make sure your dog has plenty of water to drink, to avoid dehydration. After 12 hours, introduce small but bland meals — a couple of mouthfuls at a time — such as cooked chicken or white fish and rice. Once the stools start to harden, gradually reintroduce your dog’s normal diet.

 

Does the colour of my dog’s diarrhoea matter?

The consistency and colour of your dog’s stools are important. Dog poo should be chocolate brown in colour and shaped like a log. If your dog’s stools are black and tarry this may be the result of internal bleeding. Watch out also for blood or red streaks, green stools (may signify gall bladder issues), orange stools (could be liver problems) or grey and greasy stools (potential pancreas issues).

More on this topic

Colitis in dogs

Around one-third of dogs with a history of chronic diarrhoea have colitis, which is inflammation of the large intestine or colon.  Stools are stored in the colon before it is expelled. The colon also helps dogs maintain a good balance of fluids and electrolytes (sodium, potassium, calcium, magnesium, etc). When the colon is inflamed it can result in an imbalance of fluids and electrolytes.  This often causes dogs to suffer powerful colon contractions which results in the classic symptom of frequent small amounts of diarrhoea, often with mucus or blood. Dogs with colitis often endure pain when doing the toilet.

Causes of colitis in dogs

In most cases, the causes of colitis are unknown. But infections, trauma, stress, bowel disease or genetic predisposition have been cited as causes. Diagnosis of colitis usually follows a rectal examination, blood tests and microscopic evaluation of the dog’s stools. Colitis treatment in dogs will typically involve identifying and eliminating the cause. Vets may also advise owners to supplement their dog’s diet with fibre.

Image of dog beside perfectly formed stool for Vets Now article on dog diarrhoea and colitis in dogs
Dog poo should be chocolate brown in colour and shaped like a log

My puppy has diarrhea, what can I do?

If your puppy has diarrhoea, it’s important to keep a close eye on them, especially if they’re very young. Diarrhea in puppies may be a sign of a serious condition such as parvovirus, intestinal parasites or exposure to dangerous bacteria. If your puppy has diarrhoea it’s worth contacting your vet for advice. This is especially the case if it smells foul, contains blood, is black and tar-like or if it’s accompanied by pain, fever, sickness and loss of appetite.

How to stop diarrhoea in dogs and puppies

There are several ways to reduce the incidence of diarrhoea in dogs. These include:

  • Avoid sudden changes in your dog’s diet
  • Always keep your dog up-to-date with worming and vaccinations
  • Do not give your dog bones (these can cause constipation or diarrhoea)
  • Do not give your dog small objects to play with
  • Do not feed your dog table scraps
  • Try to prevent your dog scavenging when out and about
  • Ensure all food given is treated or processed to reduce harmful bacteria