Why Do Cats Eat Grass?

(Last Updated On: November 23, 2018)

why do cats eat grass?
Image Jamie McCaffrey, Flickr

Grass contains micronutrients

As we know, cats are carnivorous,  they need to consume meat to survive. Dogs and humans can get by without meat. However, when cats hunt, they consume almost all parts of their prey including the stomach and the contents of the stomach. This may include small amounts of plant matter and the nutrients such as folic acid

To help them vomit

Hairballs, indigestible animal parts, something disagreeable, we all know what happens after our cats consume grass, they come back inside and vomit all over the floor. It’s almost as if they are doing it to spite us. This is not the case!

Grass acts as an irritant to the stomach, and cats don’t have the ability to digest grass in the way herbivores as they don’t have the necessary enzymes.   This makes sense from an evolutionary point of view because when cats eat their prey, they eat the whole thing, feathers, bones and other indigestible parts. Vomiting helps rid the digestive tract of these unwanted and undigestible products.

It is also suggested that cats eat grass so that they vomit to help get rid of intestinal parasites such as worms.

Help with the passage of hairballs

why do cats eat grass?
Image RedLipstick, Flickr

Adding to the vomiting theory, it is speculated that another reason cats consume grass is to assist with the passage of hairballs out of the body. When cats groom themselves, they inevitably ingest fur which can build up in the stomach. Eating grass can help with the passage of hairballs either from vomiting or within the feces.

It contains nutrients

In particular, cat grass contains folic acid (vitamin B9) an essential vitamin which performs several roles such as helping with the formation of hemaglobin and the synthesis and repair of DNA.

It’s enjoyable

It may really be as simple as that. They enjoy the taste of grass. Having spoken to many cat loving friends, it is no longer a surprise to hear of cats eating other types of greenery such as cucumber and broccoli. Read more on human foods cats can eat here.

What kind of grass can cats eat?

If you want to grow a tub of grass inside for your cat to nibble on, common types include:

  • Wheatgrass
  • Barley
  • Orchard Grass
  • Common oat

How to grow cat grass

Catgrass is easy to grow. Either buy a pot of cat grass or grow from seed. Place in a bright spot and water well. If you have access to seeds, add a teaspoon of seeds to the pot once a week and water well. This will keep your cat in grass indefinitely.

Better still, purchase a seedling tray from your local garden centre, this should not contain individual squares for each seed, rather a large rectangular tray, add potting mix and then seeds. Allow growing in sun. This has the benefit of providing a cat with a grassy spot to sit as well as grass to nibble on, which is especially good for indoor cats or those with access to an outdoor enclosure.

Is there a difference between cat grass and catnip?

Yes, catnip is a member of the mint family. They are completely unrelated. Catnip can also induce a high in some cats, however, cat grass doesn’t have this effect on cats.

Both cat grass and catnip are perfectly safe for your cat to eat but do bear in mind there are a large number of plants that are toxic to cats. It is recommended you don’t have indoor houseplants that are poisonous as they can in some cases lead to death. Click here for a list of plants toxic to cats.

Safety precautions

It should also be mentioned that grass grown outdoors may have been sprayed with chemicals such as weedkillers or fertilisers that can be toxic to cats, so if you have an outdoor cat, caution should be used if your cat has a tendency to nibble on the greenery.


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