Why Your Cat Might be Bringing Up Undigested Food

When your cat throws up undigested food, it’s not usually a cause for concern. However, if it continues, then it’s possibly a sign that something is wrong.

There are numerous potential reasons including a overeating, hairballs, an allergy or food intolerance.

If vomiting or regurgitation of undigested food lasts for more than two days, be sure to contact your vet.

Before looking at the causes behind the regurgitation of undigested food, it’s worth considering the difference between vomiting and regurgitation.

Difference Between Regurgitation and Vomiting

Regurgitation is actually different to vomiting. It’s a process in which cats swallow their food and then spit it back out.

In contrast to vomiting, the food has yet to be digested by the cat’s stomach.

Instead, regurgitated food comes from the mouth or oesophagus, without the abdominal effort associated with the vomiting mechanism.

Typically, the cat will either retch or expel the food from its mouth.

Reasons Why Your Cat May be Vomiting or Regurgitating

Here’s a run-down of the most common reasons that your cat may be throwing up undigested food every day.

Eating Too Quickly

It’s quite common for cats to eat too quickly and then vomit their undigested food.

Although not a cause for concern, you should try encouraging your cat to slow down at meal times.

Smaller portions as well as puzzle toys that slow their food intake can be of help here.


Cats will sometime vomit if they overindulge with their food.

If the stomach becomes stretched or bloated, the muscles responsible for moving food into the intestine become overburdened and stop working properly

Nausea and sometimes vomiting is the result. Overeating itself can be the result of diabetes, stress, pregnancy and hypertension.

Food Allergies

Cats lack lactase – an enzyme responsible for breaking down the lactose found in milk. This is whey cat’s aren’t able to digest milk or dairy products.

They also lack an enzyme called amylase that helps digest starch-rich foods such as grains and vegetables through their saliva.

Foods such as onions, chocolate, avocados, raisins and grapes are also problematic – in fact, they’re toxic to felines and are known to cause vomiting or diarrhoea.

Intestinal Obstruction

Cats with an intestinal obstruction usually present with vomiting and/or diarrhoea. They may also stop eating and drinking,


Cat hairballs are formed in the animal’s stomach and are made up of fur and swallowed food.

Although they can cause serious problems for cats, such as blockages in the digestive tract, more often than not they’re just vomited or regurgitated.

This usually occurs once to twice each month. So it’s unlikely that hairballs are the cause of your cat throwing up undigested food every day.

Dietary Changes

Cats are known to have sensitive digestive systems. As a result, dietary changes such as moving to wet and dry food can cause them to vomit or regurgitate their food.

Switching to a new brand of cat food can also cause issues. Any dietary changes you decide to make should therefore be done gradually.


A sudden onset of vomiting might be because your cat has ingested something toxic. This might include substances such as rat poison, recalled cat food or antifreeze.

Insect repellents and some cleaning solutions are known to be poisonous to cats, as are certain plants and fungi such as ragwort, belladonna, mushrooms and tulips.

Medical Conditions that Can Cause Cats to Vomit

The regurgitation of undigested food on a daily basis may be symptomatic of an underlying heath condition.

But please bear in mind that these are just potential causes. So try not to worry!


Gastritis occurs when a cat’s stomach lining becomes inflamed and ulcers form in the stomach.

This can be attributed to many factors, among them certain medications, the ingestion of toxins, kidney disease and pancreatitis.

Common symptoms include diarrhoea and frequent vomiting.


Pancreatitis is the inflammation of the pancreas which may be caused by infection, toxins or physical trauma.

Sometimes the condition develops alongside others such as inflammatory bowel disease.

The result is often pain, vomiting, diarrhoea and dehydration.

Kidney Disease

Affecting one in three cats, kidney disease often affects cats when they’re about seven years old or older.

Diabetes, hypertension and/or high blood pressure are known to be triggers.

Symptoms include weight loss, lethargy and vomiting.


Although cats don’t always show any symptoms when suffering from worms, those with serious infections will sometimes show weight loss, vomiting and have a pot-bellied appearance.

If you suspect an infection, examine your cat’s faeces or vomit for the presence of roundworms. Should you find any evidence, a cat worming treatment may prove effective.


Diabetes is quite prevalent among felines and arises when the cat’s body can’t produce or respond to insulin.

Cats with diabetes can develop kidney problems, which cause them to drink more water and urinate more frequently.

Diarrhea, vomiting and weigth loss are common symptoms.


Hyperthyroidism describes a condition in which the cat’s thyroid gland produces too much of the hormone, Levothyroxine.

It can lead to a lot of symptoms including insomnia, weight loss and heart palpitations.

The condition can also make cats very hungry which sometimes causes them to overeat. This in turn can result in regurgitation.

Hepatic Lipidosis

Hepatic Lipidosis is a condition that developers because of the presence of excess fat in the liver.

Cats suffering from this rare condition can exhibit symptoms such as weight loss, weakness and jaundice.

In some instances they’ll also vomit or suffer from diarrhoea.

How to Prevent Vomiting in Cats

So how to prevent vomiting in cats? Try to keep toxic household items away from them as well as poisonous plants/fungi such as tulips and mushrooms.

For cats that overeat, consider feeding them smaller meals throughout the day instead of one big one. Regular brushing of your cat is also an effective way of preventing hairballs.

  • Keep Toxic Items and Plants Away from Cats
  • Regular Brushing to Prevent Hairballs
  • Feed Smaller Meals Throughout Day to Prevent Overeating

Colour of Cat Vomit

Cat owners will often try to diagnose the problem by looking at the colour of the cat’s vomit.

While this can prove helpful, it’s not always reliable given that food dyes or foreign bodies can also affect the expelled fluid.

Nevertheless, here are some of the possible reasons why your cat’s vomit is a certain colour.

  • Brown, Orange, Yellow – often due to the presence of bile or partially digested food in the cat’s stomach
  • Pink or Red – could indicate the presence of blood but could also be due to food dyes or foreign bodies
  • Clear or White – can occur when the cat vomits with an empty stomach or because of the regurgitation of saliva from the esophagus
  • Green – bile can cause green vomit as can food dyes or the ingestion of foreign bodies
  • Brown or Black – resembling coffee grounds, brown or black vomit may indicate bleeding in your cat’s digestive tract

When to Consult Your Vet

Cats vomit and regurgitate quite regularly so in most instances, it really shouldn’t be a cause of concern. According to the PDSA, you should contact the vet if your cat has been vomiting for longer than 24 hours and:

  • lacks energy
  • has pale gums
  • has diarrhoea
  • has a painful abdomen
  • has blood or black dots in their vomit
  • is drinking or urinating more often than normal

Alternatively, you can use specialist apps such as Pawp to ask an online vet anything 24/7.

Useful Links

PetMD – Why Your Cat is Throwing Up and What to Do

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