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Why is my cat vomiting after introducing new kitten?

Contrary to popular belief, cats don’t normally puke. Yes, they may have a hairball they need to get rid of, but it is uncommon for your cat to be vomiting. This is a large misconception that it is normal, and you shouldn’t be alarmed.

When your cat vomits after meeting a new kitten, it could be something as simple as a response to stress, or it could be something more serious like an infection. You can look for many signs to determine why your cat has vomited.

Your cat vomiting is not a normal reaction. You need to know what the causes could be to protect your cat from any infections or malnutrition and make introducing your cat to a new kitten as easy as possible. Here is everything you need to know.

Why Is My Cat Vomiting After Introducing New Kitten?

There are many reasons why your cat may be puking with a new kitten in the home. Here are a few possible options:

  • An outlet for stress
  • An upper respiratory infection
  • Another type of infection
  • Allergy to food
  • Eating too much or too fast
  • Digestive issues
  • It may be a coincidence

An Outlet for Stress

Introducing a new kitten into your home can be a very triggering event. This is especially true if your cat is used to being by itself. If your cat has never been around another cat or never interacted with another cat, it could cause vomiting to occur.

Changing your cat’s environment (in this case, a new kitten) can overwhelm your cat. Just like humans, that stress and overwhelming feeling may come out as nausea and vomiting. It can even come out as diarrhea. 

An Upper Respiratory Infection

Kittens are more prone to having an upper respiratory infection or what is also known as the cat flu because they cannot get the vaccine. If your kitten hasn’t gotten its shots and has been around other cats, it could have an infection.

If your kitten has been around many stray cats, there is an increased chance that your kitten may have carried an infection. This infection can, in turn, be passed to your cat. 

Although your cat is already vaccinated, it can still get an upper respiratory infection that sometimes causes vomiting.

Usually, if it is an upper respiratory infection, you will see other signs and symptoms, your cat’s environment, along with vomiting. Here are some signs you may see:

  • Sneezing
  • Coughing
  • Wheezing
  • Lethargy
  • Lack of appetite
  • Lack of playfulness
  • Dehydration
  • Drooling
  • Trouble getting around
  • Difference in personality
  • Fever
cat sneezing
cat sneezing

Another Type Of Infection

Your kitten may have been exposed to many different types of infections. If your cat is suddenly puking, then the kitten may have exposed your cat to the same infection.

You may not always see the same symptoms in the kitten and the cat, but if they are both puking, that should raise some concerns.

Anytime the puking is happening more often after your new kitten’s arrival or has other symptoms involved, you may need to make an immediate appointment. This isn’t normal. Even if stress causes vomiting, it shouldn’t be associated with other symptoms.

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Allergy to Food

Sometimes, owners will buy new foods or special wet cat food when getting a new kitten. Your cat may have found a way to eat the kitten’s food. Cats can get jealous and want to show the new arrival who is boss. 

Your cat could have gotten into this new food and maybe allergic to an ingredient within it. If you didn’t change the food brands or products when getting the kitten, this might not be the cause. If you did, then it could be the cause of your cat’s puking.

Eating too Much or too Fast

Cats can sometimes be competitive or anxious at the arrival of a new kitten. They may think that the kitten is there to take their food, so they eat too much and too fast. Sometimes they may even make some weird noises while eating.

When cats do this, they can upset their stomach and end up puking it all back up.

There is also the case that the kitten may be fighting for the cat’s food, and so your cat needs to consume it as quickly as possible. Your cat doesn’t want that little kitten eating all their food. Food is important.

Digestive Issues

Your cat could be having some digestive issues due to stress and anxiety. Their stomachs could be sending all the food back because their lives are changing drastically due to the new kitten. 

Stress can cause several things that could lead up to puking. It can increase acid production and cause ulcers. It can even cause your body to think it is in flight mode.

When in flight mode, the body wants to get rid of everything inside so that the body can maneuver more quickly to get away. 

Even though your cat isn’t in immediate danger, this flight response can mess up the digestive tract. You may even see signs of diarrhea, constipation, or lack of appetite with high levels of stress. 

Could Be Just Coincidence

It could just be a coincidence that your cat puked when you brought home the kitten. If your cat vomits once and never does it again, you may not want to raise all the alarms just yet.

Keep an eye on your cat and take note of any abnormal behavior. Once you have more information, you can choose the next course of action.

How to Stop the Vomiting

There are many ways to prevent your cat from vomiting. Implement these based on what you think caused the vomiting. You may find some easier to use than others. 

Reduce Your Cat’s Stress

Reduce Your Cat’s Stress to prevent vomiting

Try to reduce the cat’s environment as much as possible. It is stressful when a new kitten arrives, so you may want to introduce them slowly. Continue reading to figure out the best tips and tricks to introducing your cat to a new kitten.


If your cat ends up getting an infection from the new kitten, you will have to contact your veterinarian. They will prescribe medication to your cat and kitten so they can recover quickly. You want to get this as soon as possible so the symptoms don’t worsen.

Change the Food Brand

If your cat accidentally got into the kitten’s food, you may want to change the food brand you have given to your kitten. You don’t want your cat to continue puking as it can cause dehydration and other problems.

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Limit Access to Food

You can limit access to food if your cat is eating too fast, or you can try to feed the kitten and cat in different locations.

This will help your cat slow down eating and reduce the anxiety that they will not get all their food. Eventually, the kitten will learn it will get food and won’t try to eat the cat’s food.

Isolate The Kitten

You may want to isolate the kitten initially, especially if you haven’t taken it to the vet. This will prevent any spread of infection, and it will allow you to introduce the kitten into your family better so that your cat doesn’t get triggered by stress.

Steps to Introducing the New Kitten

Prevent cat from vomiting after introducing new kitten

You will know what is best for your cat. It is okay to take it slow to introduce your cat to your new kitten. Most cats are good at setting boundaries without being volatile. Ensure that you don’t rush anything and do what you feel is best.

  • Introduce them after the kitten has seen a vet.
  • Do not introduce them at feeding time.
  • Feed them separately in the beginning to avoid food aggression.
  • Try not to be anxious when you introduce them.
  • Introduce them on neutral ground.
  • Allow your kitten to explore a little bit before meeting your cat.
  • Provide a few distractions so the kitten doesn’t bother the cat.

Depending on your cat’s personality and the kitten’s personality, you may not even need to do a slow introduction. Be patient with both pets. This is new to them, and it could take a few days or a week to get into the routine at your home.

When to See the Vet?

Vomiting once doesn’t mean you need to take your cat to the hospital right away. You don’t want to spend a large bill on something you could have done without medical intervention.

This isn’t always the case. There are times when you should seek a professional. Here they are:

  • Your cat isn’t eating or drinking.
  • There are other symptoms like fever and drooling, along with puking.
  • Both the kitten and cat are showing other signs.
  • Personality changes that affect physical health.
  • A drastic change in physical health.
  • Diarrhea along with puking.
  • Dehydration.

When your cat isn’t drinking or eating or having symptoms of diarrhea as well, this can cause dehydration. Dehydration can be dangerous for your cat. Always seek a vet to prevent further damage, especially with these symptoms. 

You can always call your veterinarian if you have any questions without setting up an appointment. They can tell you if your cat’s symptoms need to be seen by a professional or not. There is nothing wrong with asking questions.


Introducing your cat to a new kitten can be quite an event both mentally and physically. Ensure that you have patience for both the kitten and the cat as they adjust to a new environment and routine.

With time, they will begin to warm up to each other or learn each other’s boundaries.