Are Arborvitae Poisonous

Arborvitae (Thuja) are some of the most commonly-seen garden accents and hedging plants, so it’s important to understand their toxicity level. Fortunately, Arborvitae has a generally low level of toxicity. The oil is used in naturopathy as a topical wart treatment, but ingestion is not recommended because of toxicity caused by excessive use. The foliage can cause skin irritation in humans over time to sensitive humans, so wear gloves and long sleeves if pruning a long hedge. Some reports say dogs may experience digestive upset if ingesting a large quantity, but thujas are not listed on the ASPCA’s lists of toxic plants for humans, cats, dogs, or horses. 

Are Arborvitae Poisonous to Children

Touching arborvitae could cause potential skin irritation in sensitive individuals with significant exposure, but unless they are hiding in the hedge that’s not likely. 

Although some thujas have been used as a scurvy treatment, because of the chance of neurotoxicity from thujone oil concentrated on the tips of the leaves, you should keep young children away from arborvitae. 

Are Arborvitae Poisonous to Dogs

Puppies are known to love to chew – it helps with their teething and development. Thujas, although not listed on the ASPCA’s list of toxic plants – may cause some digestive upset (diarrhea or vomiting), according to some reports online. So, keep your pup away from Thujas in the garden. 


Are Arborvitae Poisonous to Cats

We have seen no reports about toxicity to cats in Thujas.

Are Arborvitae Poisonous to Other Animals

Thuja occidentalis is listed as potentially dangerous for horse fetuses if the mother consumed large quantities.

Symptoms of Arborvitae Poisoning

Always check with your doctor or veterinarian for guidance if you suspect Arborvitae poisoning. Symptoms of poisoning to watch for:

  • Restlessness
  • Diarrhea
  • Vomiting
  • Vertigo
  • Tremors
  • Renal damage
  • Convulsions

Consider protecting your loved ones while they are young by using barriers such as decorative fencing or wire mesh to keep children and pets from sampling your plants. Animal deterrent sprays are also an option.

Pet Poison Helpline

If you suspect your pet is suffering from Arborvitae poisoning, you can call this poison control hotline to call for 24/7 vet advice. It is called the Pet Poison Hotline, and their phone number is (855) 764-7661.

Click here for a complete list of Pet Safe Plants.


"Arborvitae." Bellarmine University.

"Toxic and Non-Toxic Plant List - Dogs." American Society for the Prevention of Cruelty to Animals.

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Author Erica Browne Grivas - Published 10-08-2021