Why Is My Cat Throwing Up Undigested Food? – 5 Reasons

Written by

Amy Sawy

Veterinarian. DVM


Joseph M. Plummer

Veterinarian, DVM, MVZ

why is my cat throwing up undigested food

Don’t you agree that cats are the most adorable creatures in this world? It is so relaxing to own a pet cat at home to befriend you whenever you don’t feel like going out for socializing. In many cases, cats become so close to us that they become members of our family.

However, there are various difficulties when owning a pet, especially cats, such as concerns about their health, their food, etc. If you have been a cat owner for a long time, I assume that you have experienced your cat vomiting after eating.

In that case, “Why is my cat throwing up undigested food”? What should you do when your cat throws up after eating? Is it alarming if your cat keeps throwing up food? How do you know if your cat regurgitates undigested food? Why has your elderly cat been vomiting undigested food recently?

Well, cats puking undigested food may result from serious health issues such as allergy, cancer, diet, etc. Hence, you should pay great attention to your cat during this period of time and consult the vet as soon as possible.

This article will answer all of those questions in the hope that it could give you a better understanding of your feline friends as well as clear instructions on what you can do for your cats. Here is a summary of what I’m discussing in the following sections:

  • Differentiate Between Vomiting and Regurgitation: The difference lies in the fact that whether the food has been digested or not.
  • The Two Types of Vomiting: Vomiting in cats can be categorized into acute or chronic. While chronic vomiting lasts for a long period of time, acute vomiting means that your cats throw up many times in a short period of time.
  • Five Primary Reasons Why Your Cat Vomits Or Regurgitates: The reasons why your cat vomits after eating include eating too fast and too much, food allergy, hairballs, changes of diet and food, and gastritis.
  • What Should You Do? Some potential treatments for your cats are medication, fluids, diet adjustment, or prednisone.

I know that you can’t wait to begin this article. Therefore, I’ll start with the first section now!


5 Primary Reasons Why Your Cats Vomit or Regurgitate


The symptoms of vomiting can be very vague, but the causes of it can vary a lot. It is even more disappointing to know that nearly any kind of illness of your cat can eventually lead to puking. However, those causes can be separated into five main reasons, and I’ll discuss each of them in the following parts.

1. Your Cat Eats Too Fast Or Too Much

One of the most common reasons why your cat’s stomach does not do a good job in digesting food is because it consumes the food so quickly that the stomach doesn’t have enough time to process everything properly.

Once your cat has been familiar with this behavior, there is a high chance that your feline friend will throw up more undigested food than you can imagine. Therefore, you should consult the vet on the training method to prevent this habit from continuing.

It might be challenging at the beginning for both you and your cat. Nonetheless, your cat will gradually eat slower and make improvements. There are several techniques you can try, and the easiest way is to feed your cat slowly.

You can either feed your cat by yourself if you have plenty of time to do so or purchase an automatic slow feeder that will challenge your cat in order to get food. These feeders can be in the form of a puzzle and require your cat’s great effort to gain food.

Alternatively and more cost-effectively, you can contain the cat food on a large plate, instead of a bowl. This will make it trickier for your cat to eat because the food will move around the plate more. You are highly recommended to meet the vet and ask for the appropriate feeding strategies.

2. Food Allergy

Cats puking undigested food can be a consequence of their sensitive stomach. In this case, it is best that you ask your vet for some advice on which food consumption your cat should take.

If the vet diagnoses what your cat is puking their food, you might want to let your cat try commercial food that is made for a sensitive system like your cat’s. Moreover, you should think of changing the cat food.

An interesting fact is that most cats are allergic to protein sources more than other nutrients ones. Therefore, receiving an appropriate diet will be tremendously beneficial for your cat’s health.

In this case, protein in food will be broken down into amino acid components, which your cat’s immune system will not be able to identify as protein. Consequently, this will decrease the likeliness that your cat has allergic reactions.

3. Hairballs

Your cat throwing up undigested dry food can be a problem, but it is even more concerning if there are some hairballs existing in your cat’s body. We all know that cats are meticulously clean, and they enjoy grooming themselves for most of the day.

During the process of grooming, the tiny “hooks” on your cat tongue may accidentally carry the loose hair from the outside of their body and into the inside.

It won’t be such a big deal if the hair is emitted. However, it will be something you should worry about if the hairballs are formed inside your cat’s stomach. Since hair is not digestible, your cat may suffer and have symptoms like nausea.

The ultimate solution for this issue is to provide your cat with some dietary supplements. In addition, it is advised that you brush your cat’s fur regularly to remove any dead hair, which the cat will probably ingest while grooming.

4. Changes in Diet and Food

A sudden adjustment of diet may cause some problems for your cat since it was not allowed sufficient time to get used to the new food. Therefore, you should do this over a couple of weeks by gradually lowering the old food amount and replacing it with the new one.

Secondly, when you apply a new feeding schedule for your cats, they will likely miss meals or eat at a different time of the day from what they normally do. Consequently, your cats can end up regurgitating undigested food.

5. Gastritis

Despite being a picky eater, there are chances that your cat eats something that they shouldn’t have. As a consequence, their sensitive stomach is irritated and your cat’s puking is a reaction to their defense mechanism.

For instance, your cats somehow manage to swallow grass into their body while playing in the garden. However, the length and shape of grass will cause a gag reflex that encourages the cat to emit this foreign body.

What Should You Do


1. Give Your Cat Fluids

If your vet does not detect any alarming symptoms after the physical exam, they may provide your cat with some fluids to detox your cat’s body. Moreover, as the cat has been vomiting a lot, this method will keep your cat hydrated.

In fact, giving fluids is the most common therapy for any cat that is vomiting, no matter what the cause is. The reason is that since cats lose a large portion of water through their vomit, they are easily dehydrated and makes them feel sick for a long time.

2. Medication

If your cat’s symptoms of vomiting are too extreme, the vet might prescribe them with some medication to stop this instantly. These pills also ease the cat’s discomfort and stimulate it to eat more food. Pain relievers will also be given if the vet thinks it’s necessary.

3. Diet Adjustment

As I have emphasized a few times in the previous sections, food sources can be a major issue that causes your cat to feel under the weather. Hence, if there is something that is irritating your cat, you should replace it with another type of food. Once again, your vet is the best person to ask for advice!

4. Prednisone

This treatment works magically for cases of cats eating food that they shouldn’t. Yet, there are a variety of side effects on your cats, such as increasing demands of water, urination, weaker immune systems and muscles.

Differentiate Between Vomiting and Regurgitation

Is it strange to know that vomiting isn’t always vomiting? In fact, I didn’t know about this until my cat threw up undigested food that the vet told me.

It is important that you differentiate these two phenomena, vomiting and regurgitation since it will give the vet more information in diagnosing the cause. So, what are the differences between vomiting and regurgitation?

In general, vomiting is when the contents in your cat’s stomach, which can be water, food, or bile, are ejected out of its body. In other words, these contents have been digested and processed by the acid in its stomach.

On the other hand, regurgitation happens when your cats eject what they consumed earlier and have not been digested. These are often contents that come from their esophagus, which is a tube that delivers liquids and food from their mouth to stomach, or mouth.

Additionally, while the cat’s vomiting is an active functional process of its body, regurgitation is a passive process since the cat only lowers its head and lets what is inside its mouth fall out. The cat regurgitating undigested food usually occurs 2 hours after a meal.

The Two Types of Vomiting

In general, vomiting can be divided into two subcategories, which are acute and chronic. When a cat chronically vomits, the cat throws up regularly, which means that there is a specific period of time in each month or week that the cat will eventually vomit once or twice.

On the contrary, acute vomiting happens in many cats who didn’t throw up before but just started to do so recently. You and your cat’s vet should be of great concern if you find your cat vomiting several times in a short duration.

So, how many times is considered to be alarming? Well, if your cat pukes no more than three times a day, it is something really normal and not worth worrying about. However, if it exceeds this number, you are strongly advised to meet the vet as soon as possible.

Some of the symptoms you should look for when your cat begins to vomit too frequently are:

  • Your cat is continuously tired and does not have the energy to walk around the house.
  • Your cat constantly consumes food but fails at completely digesting it.

Leave your cat at home for one day to see how it is progressing. If your cat’s condition starts to deteriorate considerably over the night, bring it to the nearest vet for an emergency. Any delay in getting treatments will lead to severe harm for your beloved cat since it may have a serious illness, most commonly is liver disease.

In short, make sure to check up on your cat regularly to detect any abnormal symptoms as soon as possible. Don’t hesitate to contact your cat’s vet whenever you feel anxious about its health condition.

In the following section, we will look into the five primary reasons that account for your cat regurgitating undigested food.


All in all, why is my cat throwing up undigested food? There are various causes of this phenomenon that can be hard to identify specifically. Nevertheless, being able to diagnose the main reasons will be beneficial in giving them treatments.

I hope this article is helpful. Let me know what you think in the comment section. If you find it informative, share it with your friends and family as well.

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