Colitis in dogs

Colitis is what we call inflammation of the final portion of the intestines. This is very common in dogs of all sizes and ages and can have many causes. Most cases are mild, but long-term problems can cause severe illness.

Colitis commonly causes diarrhoea and blood in the poo. Many cases are caused by stress or eating inappropriate things. These cases usually get better on their own or with a few days of a bland diet. Other causes can be intestinal worms and other infections, food intolerance and allergies, sudden food changes, and inflammatory bowel disease. Repeated episodes of colitis should be investigated.



What is colitis in dogs?

Short bouts of colitis are common in dogs and usually get better within a couple of days. If your dog is not getting better or keeps getting colitis for no obvious reason, another disease may be present.

  • With colitis, the large intestine can’t absorb water anymore due to inflammation, causing watery diarrhoea.
  • Often mucus will be produced.
  • Passing small amounts of blood is also common.
  • Your dog will be very uncomfortable and feel like they need to go immediately.
  • Often they strain for a little while even if there is little left to pass.


Symptoms of colitis in dogs

  • Soft or watery stools
  • Passing small amounts of stools many times per day
  • Having to go straight away
  • Straining or pain when pooing
  • Mucus in the stool
  • Small amounts of fresh (bright red) blood in the stool
  • Vomiting



Which dogs are at higher risk for colitis?

Colitis is a very common problem and can affect dogs of any breed, size and age. Dogs that scavenge or eat lots of hard to digest treats are at higher risk of colitis.

A specific type of colitis is Ulcerative or Granulomatous Colitis, this is common in Boxers and also happens in Frenchies and Border Collies. This can be more serious and difficult to treat. It us due to some animals having a genetic defect that weakens the defences in their colon, which allows some bacteria to get into the gut wall. This form of disease is more serious.


Diagnosis of colitis in dogs

Sometimes you will know your dog went through something particularly stressful or ate something they shouldn’t. If they are getting better, no investigations may be needed. However, if colitis keeps coming back or is not getting better, your vet may suggest the following:

  • A full physical and rectal examination to check for other signs of disease
  • Faeces tests to check for worms, other intestinal parasites and some bacterial infections
  • Special diets for 4-6 weeks to check for food intolerance and allergies
  • X-rays or ultrasound to check the shape and size of the intestines and surrounding structures
  • Colonoscopy to check the inside of the intestines and take biopsy samples if needed
  • Biopsies to rule out cancer, deep infections and inflammatory conditions


Vet treatment

Veterinary treatment of colitis in dogs

Many mild cases of colitis can be treated with home care. See below for more information. More severe or ongoing cases should be investigated and treated according to the cause. This may involve:

  • Special diets, such as hydrolysed diets for food sensitivities or high-fibre diets.
  • Probiotics and prebiotics to improve the intestinal microbiome (gut bacteria)
  • Anti-parasitic medications if intestinal parasites are found
  • Antibiotics if specific infections are present
  • Medications that reduce the activity of the immune system, such as corticosteroids


Home treatment

Home treatment of colitis in dogs


Simple cases of colitis respond very well to feeding a simple, easy to digest food for a few days. This should be:

  • Plainly cooked to improve digestibility. Boiling preserves the water content, which helps with fluid losses
  • Low in fat to make digestion easier
  • Low in residue to avoid stimulating the overworked intestine. This means food that is almost completely digested and absorbed
  • Fed in small amounts but frequents meals. This helps with the healing but avoids overstimulating the gut
  • Most dogs will benefit from fermentable fibre being added, this increases water retention in the stool and boosts good gut bacteria. Some dogs do better with low-fibre food instead.

Plain-boiled chicken or egg works well as a protein source for most dogs. This should be given with boiled rice or sweet potato. A small amount of cooked pumpkin can also be added to increase the fibre content.

The easiest way to make sure your dog is getting the right balance of highly digestible ingredients is to buy a prescription veterinary diet, such as Hill’s Prescription Diet I/D. These are:

  • Highly digestible and low in residue
  • Complete in all essential nutrients and supplemented with those that may have been lost due to the diarrhoea
  • Supplemented with the right types of fibre, pre and probiotics to help recovery


  • Probiotics (good gut bacteria) and prebiotics (food for them) are thought to help the gut recover normal function faster.
  • Some types of food-grade clay, such as Kaolin and Montmorillonite, can be used to help firm up the stools and possibly prevent absorption of some toxins produced by bad bacteria.

Living with colitis in dogs

  • Any cases of diarrhoea or abnormal stools lasting more than 5-7 days should be assessed by a vet, as an underlying problem is likely.
  • Repeated bouts of colitis without an obvious cause should also be investigated.
  • What a dog eats is the most important thing for managing long-term digestive issues. It is important to work with your vet or vet nurse to find a complete diet that most benefits your dog’s digestion.
  • Probiotic supplements appear to benefit management of chronic colitis in many dogs if they are of good quality and appropriate for their problem



Prevention of colitis in dogs

Digestive problems are very common in dogs, but a few things can be done to help prevent them

  • A healthy, balanced, regular diet will help maintain good gut health.
  • Regular treatment against worms will prevent them from disturbing the gut. Alternatively, regular faeces tests can flag when treatment is necessary.
  • Try to prevent your dog from eating things they find (or steal!) whenever possible.
  • Any food changes should be done gradually, usually around 7 days are needed.
  • If you know a stressful event is coming, some supplements can reduce the risk of colitis developing, if used in advance. Speak to a vet for advice specific for your pet; Joii can help with this.


When to worry

When to worry about colitis in your dog

Speak to a vet straight away if you notice any of the following in your dog:

  • Passing large amounts of blood in their diarrhoea
  • Very lethargic and not wanting to move
  • Repeated vomiting
  • Refusing food
  • Showing signs of pain

Joii can help assess if your dog needs a vet visit straight away or can be monitored at home.

Consult a vet - £28

Consult your vet online. Anyday, anytime.

Consult a Joii vet online for £28. Or free if you’re insured with one of our partners.

Developed by vets 🩺

QR code to app

How to get an

Join a practice

*It's free*

Download the app to register and become a member of Joii vets. In only a few taps you will have access to digital vet care 24/7 as well as a vet practice

Download the app

We’re writing as quick as we can

This article is currently being written by one of our expert vets. Check back soon.