The herb also has a strong mosquito repellent effect. And the more pieces your cat shreds the leaves into, the better it works, new research shows.

Have you ever seen a cat busy with the catnip of the same name? If so, then you know they’re going crazy. They roll around in it, chew it, and lick it like their lives depended on it. That’s not so crazy, by the way. It is well known that this plant – and for that matter also its Asian counterpart Actinidia polygama – has intoxicating properties. But this isn’t the only reason your cat loves catnip, researchers have found.

Mosquito repellent effect

catnip and Actinidia polygama contain nepetalactol; iridoids that protect the plants from pests. But not only that. Already in a previous study, researchers showed that cats that had come into contact with these iridoids were less bothered by mosquitoes. And so, in addition to getting cats high, these plants also appear to have a strong mosquito repellent effect.

crazy behavior

However, that does not explain everything. As mentioned, cats don’t just roll over catnip – which ensures that the mosquito repellents end up on their fur – they also lick and chew it. However, the reason for this remained a mystery.

A cat busy with catnip. Image: Masao Miyazaki & Reiko Uenoyama

Research leader Masao Miyazaki decided to look for answers. And in a new study he now seems to have found an explanation together with chemists. For example, the researchers noted that torn and broken leaves have a much stronger smell. So they decided to determine the concentrations of iridoids in these broken leaves.


The researchers discover that damaged leaves of catnip and Actinidia polygama Emit 20 times more iridoids than intact leaves. To study whether this change in the amount of iridoids released affects the response of cats, the team put together several iridoids cocktails. One half had a concentration of iridoids similar to that of broken leaves, the other of intact leaves. Then they served these cocktails to a series of cats.

Better operation

The cats spent much longer with the cocktails whose concentrations of iridoids match that of broken leaves. And that may explain why cats tear the leaves and lick them. The longer the cats roll through broken leaves, the more mosquito-repellent substances remain on their fur. In short, the mosquito-repellent effect of catnip and Actinidia polygama is even stronger when the leaves are torn into a thousand pieces. “We found that when the leaves are torn, they also release more mosquito repellents,” says Miyazaki. “The concentration is even ten times higher than when the leaves are still intact.”

Insect repellent

Overall, the researchers show that licking and chewing the leaves of catnip and Actinidia polygama so it definitely serves a purpose. Because this ensures that these plants become an even better insect repellent. This then effectively protects the cats against annoying mosquito bites from, among others, the Asian tiger mosquito, which can entail nasty health risks.

Thanks to the study, researchers are gradually beginning to better understand the behavior of cats. But they are not there yet. For example, the team still wants to try to find out which gene is responsible for the reaction of cats to catnip. “Our future studies promise to answer the most important remaining questions,” concludes Miyazaki.