Acute diarrhoea in Dogs

Dog Diarrhoea


Dogs with acute diarrhoea may defecate more frequently, and may have softer, looser or more watery faeces. Blood, mucus, or even parasites may be visible in or on their stools and they may have accidents in the house.

Diarrhoea is quite common and is brought on by a wide range of causes. Most cases of diarrhoea resolve in a few hours or days but ensure that your dog has plenty of fresh water available to avoid dehydration. Very old dogs and puppies, which are more susceptible to dehydration, or those already suffering from some other medical problem, should be seen by the veterinarian more quickly.

Often diarrhoea will resolve on its own. However, if your dog continues to suffer from loose stools and other symptoms for more than a day, take him to your veterinarian immediately.

If there is also vomiting, lethargy or loss of appetite, the diarrhoea is indicative of more serious causes.


Diarrhoea is characterised by stool that is soft, loose or watery.

Other signs may include:

  • Straining during bowel movement
  • Accidents in the house
  • Mucus or blood in the stools
  • Worms in the stools
  • Defecating more often

These signs may indicate a more serious problem and your dog should be seen by your veterinarian without delay:

  • Fever
  • Pain/discomfort
  • Loss of appetite
  • Weight loss
  • Weakness or tiredness
  • Abdominal pain
  • Nausea or vomiting
  • Lethargy/depression
  • Blood in the stool (black, tar-like stool or visible, red blood)


There are many reasons for your dog to have loose stools.

Here are some general causes:

  • Dietary change – change of diet or ingesting foreign objects, such as, bones, string and toys
  • Infections – viral or bacterial infections
  • Parasites – e.g. roundworms and hookworms irritate gastrointestinal tract
  • Stress – anxiety or excitement can result in gastrointestinal upset
  • Drugs and toxins – some medications can upset the gastrointestinal tract and certain toxins can also cause diarrhoea
  • Inflammatory disorders – inflammatory bowel disorders can cause your dog to develop diarrhoea
  • Metabolic diseases – thyroid imbalances or diseases in other organs, such as the liver or pancreas can upset the environment in the gastrointestinal tract resulting in diarrhoea
  • Cancer


Is diarrhoea important to assess your dog? If he seems to be happy and playful and isn’t displaying other symptoms, such as weakness, decreased appetite, vomiting and if the diarrhoea resolves itself over a period of a day, it’s probably not an emergency situation.

If your dog’s diarrhoea is prolonged and accompanied by a significant change in behaviour and an onset of other alarming symptoms, you should consider this an emergency and take him to the veterinarian immediately.


The veterinarian will perform a thorough history and physical exam to determine possible causes of the diarrhoea. Faecal examinations, blood tests and X-rays may also be needed. Advanced testing, if required, may include ultrasound or intestinal biopsy.

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