Symptom guide

Dog Diarrhoea: Causes, Home Care and When to See a Vet

Why dogs get diarrhoea, how to care for a mild case at home, and when loose stools, blood or other signs mean your dog needs a vet.

Updated October 2026 · 8 min read · By the Hushku editorial team · 2 sources

Monitor at home; call your vet if it worsens. Vet if it lasts over 2 days or other signs appear

Short answer

Mild diarrhoea in an adult dog that is otherwise well often settles within a day or two with water and small, bland meals. See your vet if it lasts more than two days, contains a lot of blood, or comes with vomiting, lethargy, fever, belly pain or not eating, and sooner for puppies and small or elderly dogs.

Key facts

Most mild diarrhoea in adult dogs settles in a day or two with water and bland meals.
See a vet if it lasts more than two days, contains a lot of blood, or comes with vomiting or lethargy.
Unvaccinated puppies with diarrhoea may have parvo: an emergency.
Return to normal food gradually over 7–10 days.

This guide is general information, not a diagnosis. If your pet seems unwell, or you're worried, call your vet.

Overview

Diarrhoea means loose or watery stools, often more often or in larger amounts than usual. It's a symptom, not a disease, and the cause ranges from a change of food to infection or chronic illness.

What it looks like can help your vet: large, watery stools a few times a day suggest the small intestine, while frequent, small stools with mucus and straining suggest the large intestine (colitis). Note the colour, consistency, how often and anything your dog might have eaten.

Go to a vet now if you see

A lot of blood, or black, tarry stools
Diarrhoea with repeated vomiting
Weakness, collapse, pale gums or a tight, painful belly
An unvaccinated puppy with diarrhoea (possible parvo)
Signs of dehydration: dry, tacky gums, sunken eyes, lethargy

Common causes

1. Diet change or eating something unsuitable
Usually mild
Sudden food changes, rich treats, rubbish or scavenged food are the most common causes.
2. Stress
Usually mild
Travel, boarding, moving house or other upheaval can trigger stress colitis, often with mucus and a little fresh blood.
3. Intestinal parasites
Needs a vet
Roundworms, hookworms, whipworms, Giardia and coccidia, especially in puppies.
4. Infections
Serious
Viral and bacterial infections. Parvovirus causes severe, often bloody diarrhoea with vomiting in unvaccinated puppies and is an emergency.
5. Food intolerance or allergy
Needs a vet
Recurrent diarrhoea can be a reaction to an ingredient; your vet may suggest a diet trial.
6. Toxins and medicines
Needs a vet
Some plants, chemicals and medicines (including some antibiotics) can cause diarrhoea.
7. Chronic gut disease and other illness
Serious
Inflammatory bowel disease, pancreatic problems, liver or kidney disease and some cancers can cause ongoing diarrhoea and weight loss.

What you can do at home

Keep fresh water available at all times; dehydration is the main risk.
For an otherwise healthy adult dog, feed small, frequent meals of a bland or vet gastrointestinal diet for a day or two.
As stools firm up, move back to the normal food over 7 to 10 days.
Ask your vet before giving probiotics or anti-diarrhoea medicines; human products can be unsafe.
Pick up stools promptly and wash hands; some causes can spread to other pets and people.

When to see a vet

Any of the emergency signs above: go now
Diarrhoea lasting more than two days, or not improving within two days of home care
Puppies, toy breeds and senior dogs, which dehydrate faster
Diarrhoea that keeps coming back, or with weight loss
Diarrhoea with fever, not eating or lethargy

Prevention

Change foods gradually
Keep up with vaccinations and parasite control
Stop scavenging with a basket muzzle if needed, and keep bins secure
Pick up after your dog and avoid areas with lots of dog faeces for unvaccinated puppies

Free tools for this

Sources

We check guides against veterinary sources and update them when guidance changes. How we write and review.

Questions.

Should I stop feeding my dog with diarrhoea?

Vets now often recommend small amounts of a bland or gastrointestinal diet rather than a long fast. A brief rest of a few hours can be fine for an adult dog, but always keep water available and don't fast puppies.

Is rice and chicken good for dogs with diarrhoea?

Plain boiled chicken and rice is a common short-term bland diet. It isn't complete, so use it for only a few days, or ask your vet for a gastrointestinal diet.

Why does my dog have diarrhoea but act normal?

Mild diarrhoea from a diet change or scavenging often doesn't affect energy. Keep an eye on it and call your vet if it lasts more than two days or other signs appear.

What does mucus in my dog's poo mean?

A little mucus often comes from irritation of the large intestine (colitis), which can follow stress or a diet change. If there's a lot, or it keeps happening, see your vet.

Key facts

Overview

Go to a vet now if you see

Common causes

1. Diet change or eating something unsuitable

2. Stress

3. Intestinal parasites

4. Infections

5. Food intolerance or allergy

6. Toxins and medicines

7. Chronic gut disease and other illness