What to do if your dog or cat has diarrhoea
the info here applies to acute diarrhoea in adult pets only
Why do cats and dogs get diarrhoea?
There are many conditions that cause pets to have diarrhoea. Some are serious. Some are not.
Almost all of the conditions that cause vomiting can also cause diarrhoea, plus there are some that just cause diarrhoea without vomiting.
When it comes to acute* diarrhoea, the main causes are:
infectious disease (eg coronavirus in dogs and cats, parvovirus, bacteria, protozoa, parasites)
dietary issues (eg bad food/toxic food, unusual food such as fatty or spicy, food intolerance)
inflammatory bowel disease (this is usually a chronic condition that has acute episodes)
acute pancreatitis (diarrhoea is seen more in dogs than cats with pancreatitis)
toxins (eg snail bait)
stress (eg change of environment/home)
*Acute refers to diarrhoea that starts abruptly and lasts for a few days (up to 2 weeks, after which it’s considered chronic)
What to do
If your adult pet has an occasional loose poo, you probably don’t need to do anything.
Otherwise, it depends on whether the acute diarrhoea is small bowel or large bowel. Here are the characteristics of each to help you know what’s what.
SMALL BOWEL DIARRHOEA
watery
large volume
not usually urgent
light coloured
soupy or greasy
not usually bloody
LARGE BOWEL DIARRHOEA
mucoid
small volume (but lots of amounts)
often urgent (gets you up at night)
darker colour
jelly like
often bloody
Small bowel diarrhoea is much more likely to lead to dehydration than large bowel diarrhoea.
First aid involves:
isolating your pet from other pets – it might be infectious
withholding food and water if your pet is also vomiting
ensuring access to plenty of fresh water if there is no vomiting
offering bland food (eg chicken and rice) for 2–3 days if there is no vomiting
monitoring for dehydration (eg looking for gum/tongue dryness, sunken eyes, skin tenting – see physical examination) especially if the diarrhoea is watery
We rarely fast pets with diarrhoea (unless they are also vomiting). The only sort of diarrhoea that is better with fasting is osmotic diarrhoea, which is unusual in dogs and cats.
Read about osmotic diarrhoea:
Seek veterinary attention/advice if:
your pet seems generally unwell (eg lethargic) or in pain
your pet is dehydrated (dry gums/tongue, sunken eyes, skin tenting)
the diarrhoea is watery and bloody at the same time or looks like strawberry jam
your pet is vomiting and the first aid for vomiting is not working
your pet refuses food
Seek veterinary advice for diarrhoea in puppies or kittens.
What not to do
Unless you have veterinary advice, do not:
give any over-the-counter medication or prescription medication to your pet
persist with at-home first aid if your pet deteriorates or fails to improve