Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

University of Illinois at Urbana-Champaign

U of I logoCollege of Veterinary Medicine

Back to search page.

Poisonous Plants and Pets Don't Mix

Pet Column for the week of January 31, 1994

Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
By Linda March
Information Specialist

House plants provide us with beauty and enjoyment, but some can also cause major
problems for your pets.

According to Dr. William Buck, director of the National Animal Poison Control Center
(NAPCC) at the University of Illinois College of Veterinary Medicine in Urbana, "a lot of
ornamental plants have irritating sap that will cause an animal to salivate or maybe vomit and
have diarrhea."

He says that plants like the hibiscus and those in the Easter lily family, which are not toxic to
people, may be very harmful to pets. Two or three days after cats have eaten a few leaves
of a Tiger lily or Easter lily, they will go into renal failure. After ingesting hibiscus, a dog will
vomit persistently, may vomit blood and have bloody diarrhea. "The loss of body fluid may
be severe enough to be lethal in some cases," Dr. Buck cautions.

Holly berries are another plant that is generally toxic to pets. Just a few berries ingested by
a pet will cause it to vomit, have diarrhea, and become generally depressed. Mistletoe also
causes digestive system upset as well as irregular heartbeats and possibly cardiac shock.
Azalea plants are very toxic to sheep and goats, but are not common problems in cats or

Plants in the nightshade family, such as European bittersweet and black nightshade, are
more erratic in their toxicity. In some individual animals it may cause digestive problems,
confusion, weakness, sleepiness, depression, and decreased heart rate, but plants of the
nightshade family don't affect all animals alike. Common houseplants, like philodendron and
dieffenbachia (dumb cane) contain oxalate crystals that cause the animal's mucous
membranes to swell, making the animal unable to eat.

"Although catnip isn't generally toxic to pets, owners should guard against giving too much
of the fresh plant to cats. This plant causes hyper-stimulation to the central nervous system
and the cat can injure itself," notes Dr. Buck. However, the dried form usually won't cause
problems for your pet.

Cats may chew on plants as a form of entertainment if they are bored. One safe release for
their boredom is to plant lawn grass in a pot for them. The grass isn't harmful, and cats may
also enjoy digging in the dirt. Dr. Buck recommends covering the soil of other houseplants
with aluminum foil to keep the animal from digging in it and decrease the likelihood of the
pet eating the plant.

If your pet does eat something that is poisonous, you should call your veterinarian. You may
also want to call the NAPCC at the University of Illinois College of Veterinary Medicine.
This center is a 24-hour, animal-based poison service.

"Many times an animal's system will react differently to substances than a human's will to
that same substance. That is why it is important for the owner and the veterinarian to
contact the NAPCC in case of an animal poisoning," explains Dr. Buck.

The NAPCC is accumulating a large database that will aid owners and their veterinarians in
treating animal poisonings.

If you have any questions on poisonous plants contact your veterinarian or the animal
poison control center at the University of Illinois. The NAPCC can be reached at
1-800-548-2423 (your credit card will be charged a $30 fee) or at 1-900-680-0000 (your
phone will be charged $20 for the first five minutes, then $2.95 per minute after that).