Talking Pets and Plants with Dr. Anna Hsieh of The Cat Practice

One of the most common "pets and plants" questions over in the HPH Facebook group is how to keep your cat from messing with your houseplants, so we decided to ask a veterinarian to weigh in on the topic. We chatted with Dr. Anna Hsieh of The Cat Practice in Birmingham, Michigan via email to find out more about why kitty might be playing in your pots, and how you can safely keep kitty out of the plants.

All of the answers in this blog post are broad, general advice, and not necessarily applicable to all cats. The Cat Practice cannot legally give specific advice to individual cats unless they have an established Veterinary-Client-Patient Relationship (VCPR). If you think your pet has been exposed to a toxic plant, you should contact your veterinarian immediately. If it is after hours, contact your nearest emergency vet. Additionally, the ASPCA Animal Poison Control hotline is available 24/7 at (888) 426-4435.

How to keep kitty out of the house plants is one of the most frequently asked questions in our group. What would you recommend to safely deter kitty from playing in potted plants, using them as a litter box, or nibbling leaves?


This is a loaded question, even though at first glance it is a simple one. The obvious answer is to physically block off the cat’s access to the plants, but realistically, many people don’t have the space to do that. Plus, we keep indoor plants because we like looking at them and caring for them in an open space in our home, it would sort of defeat the purpose of keeping houseplants and/or cats if we have to lock them away.

There are a huge range of reasons why cats have those behaviors associated with houseplants. Young cats are inquisitive, they may chew on plants because they are curious and are exploring taste and texture of new things. Some cats may do it out of boredom. It’s not so much about deterring them from plants, but more redirecting their attention from it. They can benefit from structured play times, having plenty of scratching posts and/or cat towers, toys that you can hide treats in so they are occupied through the day when you are not home. Giving them access to your herb garden can give them a safe alternative if they are insistent on chewing plants. Avoid chives/green onions/onions. Fresh lettuce and catnip plants are safe.

We find that cats generally don’t respond well to negative reinforcement, especially physical punishment. Plus, most owners are not home all the time to watch their cats, and they’ll just learn to continue the behavior when you’re not there. If you’ve given environmental enrichment a good try, and they are still persistent about bothering your houseplants, there are devices that you can purchase that make noises that interrupt undesirable behavior such as ScatMat or Scraminal.

They may be using your potted plants as a litter box because they are unhappy with their current litter box arrangements. I see a lot of cats that are brought in for pooping/peeing outside the box, and some have a medical reason for doing so (UTI/crystals in their urine) and some are behavioral due to less than ideal cat husbandry. We recommend one more litter box than the number of cats you have, because most cats as they get older like to separate their urine and their stool, and you can never have “too many” litter boxes in the house. It is also recommended to scoop their litter boxes at least daily. Try to see it from the cat’s perspective: how would you like it if you had a tiny bathroom that you only flushed once a week?

Some members suggest mothballs to deter pets, but we like to remind them that mothballs are toxic. What symptoms and problems would a cat exposed to mothballs be likely to present? How dangerous are mothballs?

Different moth balls contain different chemicals, it may or may not say so on the packaging. But if the main component is camphor, signs of exposure can manifest as seizures or other central nervous system signs. Camphor is also a direct GI irritant, you may see your cat vomiting/drooling or having diarrhea. Naphthalene can cause damage to their red cells, and eventually lead to acute kidney injury. Paradichlorobenzene can also cause damage to red cells, but may also damage their livers.

Therefore, definitely DO NOT use mothballs as deterrents. If there is a chance that your cat was exposed, try to bring the packaging of the moth ball with you to your veterinarian so they know what your cat was exposed to. In addition, we may call Animal Poison Control Center to guide us in identifying the specific toxin that the cat was exposed to and best diagnostics and treatment options. There is a consulting fee for calling Poison Control that is usually the client’s responsibility.

Are there any other commonly-suggested deterrents that are actually harmful that our members should avoid? For example, many people suggest cayenne pepper or lemon peels.


Cayenne pepper and lemon peels are safe, they generally do a good job sending a noxious message to teach a cat not to nibble on plants and don’t cause major damage to important organs. I think the issue with these sorts of natural deterrents are that they need to be refreshed, persistent cats may continue this behavior if you miss re-application of these deterrents. Redirection of the behavior will help address the issue at the root.

While we’re on the subject of toxicity, most common houseplants have at least some level of toxicity if ingested. How harmful are most common indoor plants? Are there any plants you would caution pet owners to stay well away from?

All cat owners should know: NO LILIES. We don’t know the exact toxic particle in lilies, but it doesn’t take much exposure, it has been said that a few pollen molecules can cause kidney failure. All parts of lilies are toxic to cats, it is just safer to never have lilies in the house if you have a cat.

The ASPCA has a great database on toxic and non-toxic plants here. The most common symptoms of ingestion of houseplants are GI upset because most are direct irritants to the GI tract. [Editor's note: You can also find a reference list of common toxic houseplants here on the blog.]

On the other hand, many members love to keep wheat grass or catnip for their feline friends. Are there any other plants that are good for kitty’s own garden?


Wheat grass or catnip is certainly fine for kitties. Lettuce is also okay. Common flowers such as roses, impatiens, marigold, nasturtium, sunflowers, and petunias are safe too. I would again direct you to the ASPCA’s toxic plant list for information about specific plants; there are so many out there and it would be impossible for us veterinarians to know the full list of toxic or non-toxic plants that are out there.

Thank you, Cat Practice and Dr. Hsieh for taking the time to talk with us! Remember, if you have specific questions or worries about your cat, be sure to ask your veterinarian. For more indoor gardening tips and tricks, head over to our Facebook group. Happy planting, everyone!