The 10 Issues If Your Cat Is Eating Grass and Vomiting

cat vomit

Wikipedia, Wutsje, Vomiting female cat, living at Woldzigt, a windmill in the Dutch village of Roderwolde, Drenthe.

If your cat is eating grass and then vomiting it could be:

  1. Stress eating, so use methods to de-stress it
  2. Eating grass outside the home which can have pesticides and herbicides
  3. Eating poisonous plants
  4. Have grass blades stuck which are making it sneeze
  5. Hairballs in its stomach
  6. New to having grass and so eating too much
  7. If none of these then visit the vet

Cats should not throw up after eating grass, it’s not normal.

This situation is a concern for some cat owners, and so I have researched all I can to find answers.

What follows a full guide for what to do if your cat is eating cat grass and vomiting


1. Your Cat Could Be Stressed

stressed cat

Your cat could be stress eating, just like humans can do. The cat is not eating because it’s hungry, but as a way to get rid of its stress.

A sign of stress eating, according to Vet Street is if your cat is constantly eating. Cats that go outside may find other things to chew, but inside grass and maybe even household plants are what they can chew on.

Their stress can be caused by not having been socialized or exposure to negative experiences early in life. Our cat Archie is a rescue cat who still has issues from his traumatic childhood.

A good way to solve this is to give your cat other things to occupy it, such as games, puzzles, or teaching it basic tricks.


2. Make Sure Your Cat Is Not Eating Grass Outside Your Home

outside cat grass

Make sure you grow your cat grass without using pesticides or herbicides.

You can’t be sure of this if your car cat eats some outside your home. The treated grass may not cause vomiting, but can give your cat internal parasites and be toxic to them.

If you know the person who is growing the grass, such as if they are a friend or neighbor, they can tell if you if they have treated it, and then it’s fine.

However if they use a gardening service, that service may have put pesticides or herbicides on it without their knowledge.

If your cat is vomiting daily, then keep it at home for a while so you can be sure it is not eating stuff outside your home that is causing the problem, and see if it stops.


3. Make Sure Your Cat Is Not Eating Plants in Your Home Which Could Be Poisonous to It

Make sure your cat can’t eat other plants and vegetation in your home, which may be poisonous to it.

Also, make sure your cat cannot get to other plants in your home which may be dangerous for them.

I find it’s essential to make sure Archie has lots of grass in our home, so he does not have the need so much to eat other plants in the home, and grass from outside. I make sure his grass is lush, green, and there’s always a spare one on hand for if it gets mold or any other problem.


This list of plants that are dangers for cats from the American Society for the Prevention of Cruelty to Animals is excellent.


4. Stuck Blades of Grass Causing Sneezing

cat sneeze

A cat can start to sneeze because of grass stuck to the back of its nose, or inside of its nasal chambers. Then a vet needs to remove it as quickly as possible.


5. Your Cat Could Be Vomiting for Other Reasons Such As

long haired cat hairball

Wikipedia, A hairball from a Maine Coon cat (about 4 in/10 cm long). Photo by Derek Jensen (Tysto), 2005-December-22.

This is an example of a hairball from a long-haired cat. Usually, hairballs have more liquid, but I chose this photo as I did not want to show more disgusting ones.

Cats bringing up hairballs is normal.

When cats lick their fur to groom and clean themselves, they also swallow hair and can’t digest it. The hair comes out as a big hairball vomit.

Did you change your cat’s diet, food, or brand you are feeding it? Cats can take a few days to get used to a new food type, and if yours is still vomiting after a few days you may need to change it back again.


6. I Have Only Just Started Giving My Cat Grass, and He Is Eating an Excessive Amount

archie want grass

The first time I gave Archie grass, he was really really excited and ate loads and loads of it. Archie looked at me while I was preparing it, like I should have always been giving it to him.

 He could not get enough and finished a whole plant pot full of the stuff.  I decided not to grow it in massive quantities to try and keep up with him, because anything in excess is not good.

If you have just introduced your cat to eating grass, and it gorges itself on the grass. Maybe time to hide it for a lot of the time and only bring it out for a short while. Then leave the grass out more and more as your cat is used to the novelty and can control himself.

I put the grass out of his way by putting it on a shelf high up above my hob which also has my cooking equipment.  

I make sure the grass is behind something so he can’t see it, which for him would be like putting temptation right in front of him. This place also gets lots of light, and Archie knows he is not allowed there and has a hard time getting to it.


7. Just Because the Grass Is in Your Cat’s Vomit, Does Not Mean It’s the Cause

Cats eat grass and get what they need from it, but cannot fully digest it as they do not have the enzymes to break down vegetation.

So grass either comes out in poop or come out with their vomit if they do so. So don’t worry if the grass is in the vomit, it does not mean it caused it.


8. Are You Giving Your Cat a Suitable Type of Grass

There are lots of different types of grass, and others you can give to cats, but the most commonly accepted type of grass to feed cats is oat grass.

Some people call it by its latin name of Avena Sativa.

People often feed their cats other ones though such as rye, barley, and wheat grasses which are all fine.


9. It’s Still Good to Feed Your Cat Grass

grey and white short fur cat

I have been doing detailed research on the subject, and have put the sources of that research below this article. I have also and spoken to lots of cat owners and vets over the years. I cannot find a single reason to stop letting your cat eat grass, and can find many reasons why they should get it.

There are so many, and here they are:

Cats eating grass gets rid of the waste in their digestive systems, which otherwise can cause them problems.

It also contains folic acid, which is an important vitamin for cats and helps them produce hemoglobin protein, which moves oxygen around their blood. Not enough folic acid can make a cat anemic or stop it from growing. A cat will automatically eat grass if it knows it does not have enough folic acid.

Grass helps a cat poo because it works as a laxative for them. This stops digestion and means the hair in their intestines can go out with their poop, rather than coming out in their vomit.

If a cat has a chronic GI (gastrointestinal disease), which can make it lose vitamins, cats will eat grass to try and get more of them. The grass can also wrap around the GI parasite to help the cat get rid of it, and the parasite usually comes out in its poop.

Cats eat grass to settle their stomachs, a bit like how people will take an antacid.

My cat Archie is a house cat, so he does not have so much to do. Getting his grass is a big deal for him and important activity. He will even show other people his grass to show off his possession.

Cats in the wild naturally eat grass, so you are giving them the most natural life possible.

Giving your cat grass to eat is a good thing to do, but usually not essential. Many owners don’t give their cats grass to eat, and their cats are fine.


10. When It’s Time to Go to the Vet

If you are concerned that the vomiting is a bit more serious, then immediately take it to a vet.

Also, look out for other signs such as if it is tired and so on, which could also indicate other problems.

Your cat should be eating the grass now, or then. If it is eating loads it could be a sign that your cat is having intestinal problems and is trying to eat the grass to solve them.


Writer: Ian Taylor

ian taylor archie cat