Why do cats eat grass and how does it affect them?

1 July 2021

Cat eating grass? Learn why, what to do about it, and how to keep your cat safe when they're out and about.

brown cat outdoors

Fact. When you live with a cat, you’ll come across some question-raising behaviors. What is it, for example, with their tongue sometimes just casually sticking out? And why do cats eat grass? Most quirks are just cute, but in this case, it’s good to know if your cat eating grass is safe. Find out why it’s perfectly normal, and what to watch out for. Plus, discover some natural grass alternatives for your cat. While you’re here, find out if your cat suffers from a pollen allergy and what you can do about it.

So it’s official – cats eat grass. You’ve likely already seen this from your own furball. But now, thanks to a survey from the University of California Davis Veterinary School of Medicine, you can see the bigger picture too:

  • 89% of cats ate grass six or more times throughout their lives
  • 11% of cats were never observed eating grass
  • 91% of the time, cats appear in good health before eating grass
  • 27% of cats vomit frequently after eating grass or other foliage1

This shows that nearly all cats eat grass – and are typically A-OK when doing so. A widely-believed (but not 100% accurate) explanation for why cats eat grass is that it helps them vomit if they got sick or poisoned. But that’s not always the case. The researchers found that, after eating grass, most cats do not throw it up – or show any signs of illness1. Cats can be purrfectly healthy, and still eat grass. So that brings us to the question – why do cats eat grass anyway?

Why do cats eat grass?

In short, cats eat grass because its comes naturally to them and can support their health – in the same way eating leafy greens helps us humans stay healthy. Here are 5 reasons why cats eat grass:

  1. Cats actually lack the stomach enzymes needed to break down and digest grass. As a result, it sometimes… comes back up. And together with it comes other stuff they can’t digest, like hairballs or inedible parts of prey such as fur or bones. We know, eww. But it’s good for them!
  2. The fiber found in grass supports digestion and can help relieve constipation.
  3. Anxious or stressed cats may find that chomping on grass helps calm their nerves. A bit like chewing gum for felines.
  4. Cats may eat grass as a source of vitamins and minerals, such as folic acid (B9), that they may not be getting elsewhere.
  5. Eating grass may help your cat get rid of internal parasites (or at least, this may be a leftover instinct from your cat’s ancestors)2.

Plants like grass contain fiber and other nutrients that are good for cats.

When to be concerned about your cat eating grass

If your cat is eating grass every day or vomiting blood, there is definitely cause for concern.

⚠️ Warning: Munching on grass every day might indicate problems with your cat’s digestive system.

The more trouble they have digesting their food, the more they will crave grass in an attempt to clear it out. On the other hand, your feline might, eventually, stop eating altogether.

Find out what to do if your cat won’t eat.

Note: If your cat is vomiting blood, it is possible that they’ve ingested toxins, possibly in the form of pesticides or other chemicals found outside. Should this be the case, don’t hesitate and take them to the vet ASAP!

outdoor brown cat eating grass

Cat eating grass? 3 tips to keep them safe

Even though your cat eating grass on occasion is generally no cause for concern, there are certain steps you should take to ensure your cat’s safety.

1. Beware of pesticides.

If you have a garden (a.k.a. your cat’s mini-empire) make sure it’s a cat-friendly one:

  • make sure not to use any insecticides or herbicides
  • check for any toxic plants that might be growing there (more on that below)

2. Provide cat grass at home.

If your cat is used to roaming the whole neighborhood, it gets trickier to avoid pesticides and other dangers. A good tip? Don’t let them eat anything and everything they come across.

Of course, that’s much easier said than done. A better option is providing cat grass at home, which you know is safe to eat.

beige cat eating grass from dish

Cat grass seeds, usually oat, barley or wheat, should be available at most pet stores. You can also grow it yourself in pots or outside – a fancy alternative to the greens sprouting next to busy roads or on dog-marked territory.

3. Keep your cat away from toxic plants.

If you keep your cat indoors, make sure to provide them with cat grass as well and remove all toxic plants that they might nibble on. Whether your cat spends a lot of time outdoors or indoors, it’s useful to know this list of common toxic plants:

  • Amaryllis
  • Dieffenbachia (also known as Dumb Cane)
  • Lilies
  • Heartleaf Philodendron (also known as horsehead philodendron)
  • Aloe plant
  • Sago palm

The list goes on, so make sure all your plants are non-toxic to cats before bringing them home.

Ingesting toxic plants can induce anything from stomach bleeding to liver failure, and be deadly.

What is a good alternative to offering cats eating grass?

Now that you know why cats eat grass (and throw up grass), you know they’re just keeping themselves healthy.

However, safer is always better. That’s why, as mentioned, it’s a good idea to look into cat grass, which is definitely safer and can satisfy your cat’s appetite for grass.

If your cat has a habit of wandering far from home, looking for snacks, then it’s a good idea to keep track of them with the help of a GPS cat tracker.

You’ll also be able to see where they’ve been on the map, which can help you mark out areas to watch out for.

Track My Cat

Top reasons why your cat is eating grass

Simply put, cats eat grass because it comes naturally to them. It’s an instinct ingrained in them long ago by their ancestors. Eating grass has a number of health benefits, which helps to explain why even our domestic kittens like to munch on the green stuff.

A quick summary of why your cat is eating grass, you say? You’re welcome 😉


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