Are Ferns Poisonous to Dogs?
Varies by species (e.g., Nephrolepis exaltata 'Bostoniensis' for Boston fern; Asparagus densiflorus cv. sprengeri for the misleadingly named 'asparagus fern') · Varies (Dryopteridaceae for Boston fern; Liliaceae for asparagus fern; Polypodiaceae for bracken fern)
Ferns are mildly toxic to dogs.
Why it's toxic
The toxic compounds in ferns:
- Depends on the specific plant; 'asparagus fern' (Asparagus densiflorus) contains sapogenins in its berries
- Bracken fern (Pteridium aquilinum) contains thiaminase (ASPCA lists toxicity to horses; caution warranted for dogs)
Symptoms to watch for
If your dog ate ferns, watch for:
- Asparagus fern: allergic dermatitis with repeated dermal/skin exposure
- Asparagus fern: gastric upset if berries are eaten — vomiting, abdominal pain, or diarrhea
- True ferns (e.g., Boston fern): generally none expected; mild GI upset (vomiting/diarrhea) is still possible if a dog eats large amounts of any plant material
What to do if your dog ate it
- 1Remove your dog's access to the ferns and check how much may have been eaten.
- 2Do NOT induce vomiting unless a veterinarian or poison-control expert specifically tells you to.
- 3Call your veterinarian, the ASPCA Animal Poison Control Center (888) 426-4435, or the Pet Poison Helpline (855) 764-7661 right away.
- 4Note the amount eaten, the time, and your dog's weight and any symptoms — have this ready for the expert.
- 5Follow professional guidance and go to the nearest emergency vet if you are advised to.
A consultation fee may apply to the Pet Poison Helpline. When in doubt, contact your own veterinarian or nearest emergency clinic.
Frequently asked questions
- Are Boston ferns safe for dogs?
- Yes. The ASPCA lists the Boston fern (Nephrolepis exaltata 'Bostoniensis') as non-toxic to both dogs and cats. It is one of the safer fern choices for a home with pets, though a dog that eats a large amount of any plant may still get mild stomach upset.
- Why is my 'asparagus fern' listed as toxic if Boston ferns are safe?
- Because the asparagus fern is not a true fern — it is Asparagus densiflorus, in the lily family (Liliaceae). The ASPCA lists it as toxic to dogs: its berries cause vomiting, abdominal pain, and diarrhea, and repeated skin contact can cause allergic dermatitis. Common names are unreliable, so always check the scientific name.
- What about bracken fern growing outdoors?
- Bracken fern (Pteridium aquilinum) contains thiaminase, which depletes thiamine (vitamin B1). The ASPCA documents toxicity in horses (weakness, weight loss, staggers, tremors, death). It is prudent to keep dogs from grazing on wild bracken and to contact a vet or poison control if ingestion is suspected.
Sources
Related plants & foods
This page is for general educational purposes and is not a substitute for professional veterinary advice. Toxicity can vary with the amount eaten, your dog's size, and individual sensitivity. If you suspect poisoning, contact a veterinarian or poison-control hotline immediately.