Behavior
A brown tabby cat eating grass.
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Is Your Cat Eating Grass? Here’s Why

Cats eating grass is a behavior that goes way back. Let’s look at the reasons why cats eat grass and what kinds of grass they should avoid.

Angie Bailey  |  Sep 11th 2017


Why is your cat eating grass? Cats have actually eaten grass throughout history. Although they’re generally not too particular about the kind of grass they choose, some humans offer their felines cat grass, which is a safe and controlled alternative for kitties to get their greens. Despite what some believe, cat grass is not the same as catnip, which is a member of the mint family. Cat grass typically grows from rye, barley, oat or wheat seeds.

Felines are obligate carnivores, which means they can live a healthy life eating only animal protein. So why are cats drawn to eating grass? Even if they’re fed a highly nutritious diet, most every cat enjoys chomping on many varieties of the green stuff, and there are good reasons for this proclivity.

Cats eat grass for digestive aid

A cat eating cat grass.

A cat eating cat grass. Photography by AllaSaa/Thinkstock.

In the wild, cats sometimes eat grass after they’ve ingested their prey — and the prey itself likely had grass in its digestive system. Grass stimulates the cat’s urge to vomit, which can be nature’s way of expelling the parts of the prey that are not digestible. This is an instinctive behavior that all cats share.

Cats eat grass for hairball control

Hairballs develop when a cat grooms himself. The feline tongue has tiny, hook-like structures that act as a brush, catching the loose hair as he grooms. Most of the hair passes straight through the cat’s system, but the hair that stays in the stomach forms hairballs. They’re uncomfortable, so kitty’s biological impulse it to get rid of them. Ingested grass activates the vomit reflex, thus removing the hairballs from the cat’s body. Regular brushing can lessen the likelihood that hairballs will develop.

Cats eat grass to get vitamins and minerals

Cats may instinctively ingest cat grass for nutritional purposes. It contains trace amounts of vitamins A and D, as well as niacin. It also includes chlorophyll, which helps oxygenate the blood. Additionally, there’s folic acid, a protein that helps with the production of hemoglobin. Like humans, cats’ bodies often crave what they need nutritionally.

Buying cat grass

Cat grass seeds or kits are available at pet supply, health food or garden stores. They’re easy to plant: Soak the seeds for 6 to 8 hours and then place them in a planter with soil. You can also plant cat grass outdoors so kitty can dine al fresco in an enclosed catio or while on a harness.

When to start offering grass to cats

Cats of almost any age can enjoy the benefits of cat grass, but offer it in moderation to kittens. Robin AF Olson, President and Founder of Kitten Associates cautions, “Adult cats love to eat grass, but I’d go easy on it with kittens. Since they’re usually ready to eat anything and everything, offer it in moderation so they don’t overdo it. Also, I wouldn’t give it to them until they’re at least 4 months old. Any younger than that, and it is too challenging on their developing digestive tract.”

Warning — not all grass is safe for cats  

If you take your cat out on a harness, don’t let him eat just any old grass. Grass outdoors runs the risk of having toxins from pesticides!

As always, make sure all the plants in your home are nontoxic to cats. If kitty is used to eating cat grass from a planter, he may think it’s OK to ingest other indoor plants, too. The ASPCA’s site provides a comprehensive list of plants and flowers that are poisonous to cats.

So go ahead and offer your kitties the greens they crave — just do it safely and thoughtfully.

Thumbnail: Photography by Nereids/Thinkstock.

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