My Dog Has Diarrhoea: What to Do and When to See a Vet

Diarrhoea is one of the most common health complaints in dogs. A single bout of loose stools, particularly after a dietary change or a scavenging incident, will often resolve on its own. However, persistent diarrhoea, blood in the stools, or diarrhoea combined with vomiting or lethargy needs prompt veterinary attention.

Is This an Emergency?

Go to a vet or emergency clinic immediately if your dog:

• Has blood in the diarrhoea (especially if it is bright red or very dark and tarry)
• Is also vomiting repeatedly and cannot keep water down
• Is a puppy, elderly, or has a known health condition
• Is showing signs of severe abdominal pain
• Is weak, lethargic, or has collapsed

Call your vet the same day if:

• Diarrhoea has continued for more than 24 hours in a puppy or more than 48 hours in an adult dog
• Your dog is also vomiting, has a reduced appetite, or seems unwell in any other way
• You suspect your dog has eaten something toxic or unusual

Wait and monitor for up to 48 hours if:

• Your dog has had one or two bouts of loose stools, is otherwise bright and well, and is drinking normally
• There is no blood and no vomiting
• There has been a recent change in diet or your dog has been scavenging

What Causes Diarrhoea in Dogs?

Dietary indiscretion

Eating rubbish, scavenging, or a sudden change in diet is the most common cause of acute diarrhoea in dogs. The gut is sensitive to rapid dietary change; always transition to new foods gradually over seven to ten days.

Bacterial or viral infection

Infections including Campylobacter, Salmonella, and parvovirus can cause acute, severe diarrhoea. Parvovirus is particularly dangerous in unvaccinated puppies and young dogs.

Intestinal parasites

Roundworms, hookworms, whipworms, and the protozoan parasite Giardia can all cause diarrhoea. Regular worming and vet-prescribed preventative treatment help reduce the risk.

Inflammatory bowel disease (IBD)

Chronic diarrhoea in dogs with weight loss and appetite changes may indicate IBD, an immune-mediated condition requiring long-term dietary and/or medical management.

Stress colitis

Emotional or physical stress can trigger a bout of diarrhoea, often with mucus or blood, known as stress colitis. It is common after kennelling, a house move, or a change in routine.

Medications

Antibiotics commonly disrupt the gut flora and cause diarrhoea. If this occurs after starting a new medication, speak to your vet.

Which Breeds Are More Prone to Diarrhoea?

• German Shepherd: High incidence of exocrine pancreatic insufficiency (EPI) and IBD, both of which cause chronic diarrhoea
• Irish Setter: Genetic predisposition to gluten-sensitive enteropathy, a condition similar to coeliac disease in humans
• Yorkshire Terrier, Maltese: Small intestinal bacterial overgrowth (SIBO) and protein-losing enteropathy are more common in small breeds
• Labrador Retriever: Prone to dietary indiscretion due to indiscriminate eating habits

What Will the Vet Do?

For mild, self-limiting diarrhoea your vet may advise rest and a bland diet over the phone. For more persistent cases they will:

• Examine the abdomen and assess hydration
• Take a faecal sample to check for parasites and bacteria
• Recommend blood tests if systemic illness is suspected
• Prescribe gut-supportive treatments, probiotics, or antibiotics as appropriate

How to Help Your Dog at Home

For mild diarrhoea in an otherwise well adult dog:

• Offer a bland diet: plain boiled chicken and white rice, or a veterinary prescription gastrointestinal food
• Ensure fresh water is always available to prevent dehydration
• Feed little and often rather than one large meal
• Reintroduce normal food gradually once stools have improved
• Do not use human anti-diarrhoea medications such as Imodium without veterinary advice