Cat Colitis: Causes, Signs and Treatment

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Have you noticed your cat straining to go to the toilet? Maybe some diarrhoea, or blood or mucus in their poo? If so, your cat may be suffering from colitis, or inflammation of the large bowel. This can be pretty uncomfortable for them and, with possible causes ranging from mild to serious, it’s important to try and spot it early and find out what’s going on.

Causes of cat colitis

Colitis is most common in cats under five years old but can occur at any age. Some of the most common causes are:

  • Food-responsive enteropathy (FRE). FRE is one of the disorders that were previously called Inflammatory Bowel Disease (IBD). Nowadays, together with other disorders such as steroid-responsive enteropathy, the more general term chronic enteropathy (CE) is used. CE is used to describe any chronic disorder of the GI tract, typically any condition lasting more than three weeks.
  • Adverse food reactions. Allergies and intolerances to certain foods can cause colitis. This is likely to continue until the offending ingredient has been eliminated from the diet.
  • Parasites.
  • Stress. Stressful events, like a new baby or a trip to the cattery, or just living with other cats, can cause colitis.
  • Tumours and polyps in the bowel.
  • Infections.
  • Swallowed foreign objects.

Signs of colitis

As we mentioned, the most common signs of colitis are blood and mucus in the poo. Sometimes there will be diarrhoea too, and you may notice your cat straining to go to the toilet or spending more time in the litter tray than usual. This is because they feel like they need to go even when they don’t. It’s very important if you see your cat straining that you seek prompt veterinary advice. This is partly because colitis needs treating, but also because straining can be a sign of cystitis or a blocked bladder and this is a medical emergency.

Any digestive or toileting issues can be tricky to spot if your cat goes out to go to the toilet. If colitis goes on for some time (chronic colitis), you might notice your cat losing weight, becoming lethargic, or going off their food. As with all things when it comes to our pets, it’s a good idea to be observant. If you know what’s normal, you’ll soon spot when something is up.

Treating colitis

Naturally, with lots of different possible causes, the treatment for colitis will vary depending on what the issue is. Many cases get better within a couple of days, particularly those caused by a cheeky stolen treat, but if it persists for more than 48 hours or your cat seems in pain, then a vet visit is needed. It will help if you can take a sample of poo with you, as your vet may want to test for signs of worms or infections.

Treatments include:


  • Changing the food. Because many cases of colitis are food-responsive, your vet may want to put your cat on a highly digestible food aimed at supporting a quick return to a healthy gut. These foods often have good sources of prebiotics to nourish the bacteria that keep the gut healthy. Your cat may only need to have this food for a limited period of time, but you can keep them on it if you and your vet feel it’s a good choice in the longer term.

  • Some cases of colitis will need anti-inflammatories. Steroids are very good anti-inflammatories and may be used just for a few days, or longer if the condition is chronic.

  • If your vet suspects your cat may have an allergy or intolerance, they may recommend a diet trial. This usually consists of feeding a food with hydrolysed proteins that can’t cause an allergic reaction in your cat. Or sometimes they might suggest a protein source your cat hasn’t had before, such as duck. Your cat may need to stay on this new food for life.

  • Antibiotics may be given if your vet is concerned about antibiotic-responsive enteropathy.

  • If your cat has worms, your vet will treat them and advise about ongoing prevention.

  • Stress is pretty common in cats, especially if they live with other cats or there are lots of neighbouring cats in the area. Your vet may give medication to help with stress, but often changing the home environment and using things like plug-in pheromone diffusers can make a huge difference, too.

  • Tumours, polyps and foreign objects in the bowel may require surgical intervention.

Colitis in cats is usually not much to worry about, but it’s important to investigate just in case it’s caused by one of the more serious issues. Your vet would always rather see you early on than risk your cat getting very sick, so don’t be afraid to ask for help if you have any concerns!

Reviewed by Dr. Hein Meyer, DVM, PhD, Dipl-ECVIM-CA