Vomiting and diarrhoea in cats

Your cat's faeces should be shaped. Loose stools or hard "harlots" are abnormal. Cats may throw up balls of hair every now and then, but a cat shouldn't vomit multiple times a week. Most hair a cat ingests is passed out in the faeces.

An acute episode of vomiting and diarrhoea in cats often resolves within 12-48 hours. If not, it is time to contact a vet for advice and a possible visit.

Vomiting in cats

You need to distinguish whether it is vomit or regurgitation. When vomiting, the cat howls and you can see that the abdominal muscles are working to bring up food from the stomach and the front part of the small intestine. In a regurgitation, food or liquid comes up without effort.

Regurgitation and vomiting have different causes, so it is good to know the difference. A video to show your vet can help if you are unsure yourself. Intense vomiting without diarrhoea may indicate that something is stuck in the intestine and a veterinarian should be consulted. Find out what to do if your cat is being sick.

Different types of diarrhoea

Acute diarrhoea lasts for a shorter period, it could be one to two weeks. Chronic diarrhoea lasts for a long time and should always be investigated.

• Acute diarrhoea can often be mild and go away by itself. As long as the cat's general condition is normal and the cat has no other symptoms, you can wait.

Diarrhoea is divided into small intestinal and large intestinal diarrhoea.

• Small intestinal diarrhoea: larger amounts of loose stools come as often or a little more often than normal.
• Large intestinal diarrhoea: your cat will toilet much more often than normal, but only small amounts of faeces come out at a time. The faeces may also have a film of mucus and some fresh blood.

A combination of small and large intestinal diarrhoea is also possible.

Occasional small drops of fresh blood in your cats stool are not dangerous. If, on the other hand, the faeces become black and resembles tar, or contains large amounts of dark blood, a veterinarian should be consulted immediately.

Common causes of vomiting and diarrhoea

Vomiting and/or diarrhoea can either be due to problems in the gastrointestinal tract only, or it can be due to some other disease that the cat has that affects the stomach and intestines.

Young cats usually get vomiting and/or diarrhoea from infections or from eating something inappropriate. Very young kittens can also have deformities. In the worst case, objects can get stuck in the intestine and have to be surgically removed. Older cats' symptoms are more often caused by another disease such as hyperthyroidism, liver disease, kidney disease, IBD (inflammatory bowel disease) or tumours.

• Ate something inappropriate
• Feed intolerance
• Infections e.g. parasites (e.g. tritrichomonas, roundworm), bacterial infections (e.g. salmonella in cats that hunt small birds), viral infections (e.g. parvovirus (feline plague) or coronavirus)
• IBD (inflammatory bowel disease)
• Inflammation of the pancreas (pancreatitis), liver or kidney damage
• Hyperthyroidism
• Foreign body (object stuck in the intestine)
• Stomach catarrh/stomach ulcer
• Deformities
• Tumours
• Poisoning

What can you do at home?

A cat with acute vomiting and diarrhoea that is still alert and has no other symptoms can usually be treated with at home.

In case of diarrhoea, the recommendation is no longer to starve cats. Cats have a fast metabolism and cannot survive starvation for any length of time. Instead, give small portions of a gentle diet - make sure it is low in fat and easy to digest. Special food for acute gastroenteritis can be purchased from a veterinarian.

Give the food divided into many meals per day. Start with a few teaspoons every two hours, then increase the portion size and reduce the frequency as the cat feels better. You can also give the cat boiled white fish or boiled chicken, without bones and fat, for a couple of days.

Don't give your cat homemade food for more than a week or so, as it lacks a lot of the important nutrients that they need.

Homemade dog food for cats

• Boiled white fish or
• Boiled chicken without bones or fat

Keep in mind that your cat will be losing a lot of water and needs to take in more liquid than usual. Fluid replacement can be boiled yourself from a litre of water, a tablespoon of dextrose and a teaspoon of salt, but also give the cat free access to plain water. Cats with large intestinal diarrhoea can do well with fibre supplements in the food - however, this is a more chronic treatment and should be discussed with your veterinarian after examining the cat.

Fluid replacement to be done at home

• 1 litre of water
• 1 tablespoon dextrose/sugar
• 1 teaspoon of salt

Read more about fluid replacement for cats

If your cat vomits, you can refrain from feeding them for a couple of hours and then carefully try to give small portions of the diet food above. A cat that can't keep food or water down should be examined by a veterinarian.

When should you seek care?

• If the cat's general condition becomes bad (lethargy, fever or dehydration)
• If the vomiting is very violent
• If the diarrhoea is black (a few drops of red fresh blood is not dangerous)
• If there is blood in the vomit (often looks like coffee grounds)
• If the cat is in pain
• If the cat does not want to eat
• If the skin, mucous membranes or whites of the eyes become yellowish
• If the symptoms have not disappeared in 12-48 hours despite a poor diet or if the cat has constant relapses

Written by Amanda Andersson, July 2024. Approved by licensed veterinary specialist Catarina Eliasson.