Poisonous Plants Abound in House, Yard

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I will never forget the day my son sampled a houseplant leaf. Although I didn’t see him insert the pothos into his mouth, I did hear his screams. Alarmed, I called the poison control center and discovered why one little leaf can create such a scare.

Pothos and many other common houseplants have oxalate crystals in their juice or sap. These microscopic crystals resemble tiny needles or splinters of glass. When plant leaves are chewed, the crystals are released and there is mouth pain. Fortunately, young children have few teeth and don’t release as many oxalate crystals when chewing as older children and animals, so the pain may only last a couple of hours.

It turns out that my call is a common one.

Anthony Manoguerra, a pharmacist who is director of the San Diego division of the California Poison Control System, which serves Orange County, said 80% of the 2,500 calls a year received about potentially poisonous plants involve those with oxalate crystals.


“These plants cause irritation of the mucous membranes; pain and/or swelling of the mouth, lips and tongue; and skin rashes, with symptoms lasting about a day,” he said. “Eating these plants usually isn’t life-threatening, unless there is enough swelling to obstruct breathing.”

Plants that fall into the oxalate category include dieffenbachia, philodendron, pothos, elephant’s ear (Alocasia), caladium species, peace lily (Spathiphyllum), Swiss cheese plant (Monstera deliciosa) and arrowhead vine (Syngonium podophyllum).

While many indoor plants aren’t potentially deadly if ingested, a surprising number of outdoor plants can produce life-threatening reactions when their leaves, flowers or fruit are eaten.

Many of these toxic plants can damage the heart and other major organs, and their ingestion can be fatal. There are other categories of plants that cause rashes when plant sap comes in contact with skin. And many other types of plants also cause vomiting and diarrhea when eaten.

Whether dehydration will occur depends on the type of plant and the amount ingested. Manoguerra said a child became dehydrated after eating castor beans. “There was potential for liver damage, and the child had to be hospitalized,” he said.

Other symptoms that may be seen after ingesting a poisonous plant include nausea, headache, lethargy and a drop in heart rate, usually occurring within six to 12 hours. What occurs depends on the quantity and type of plant ingested.


If you suspect that a child has eaten a potentially poisonous plant, call the Poison Control System immediately at (800) 876-4766.

“Most children who have taken a small bite out of a harmful plant will be fine, but the poison control center should be the judge of that,” Manoguerra said. “Unlike dogs and cats, children will rarely eat large amounts of a toxic plant because most have a very unpleasant taste.

“Oleander is an example. Although it is poisonous, it’s so bitter that most kids stop eating it once they start and don’t ingest enough to cause much harm.”

When you call the poison center, describe exactly what happened, including when the child ate the plant, how much and which parts. If you don’t know the name of the plant, send someone to the nursery with a plant sample for identification while you call, or download photos of various highly toxic plants off the Poison Control System’s and the ASPCA Animal Poison Control Center’s Web sites (see addresses at end of story).

Treatment for a plant poisoning varies, depending on the plant ingested and the amount. If the plant eaten is an oxalate, wipe out the mouth and give the child something cool to drink to alleviate the discomfort. Popsicles work well to reduce swelling and relieve irritation.

To protect children and pets from plant poisoning, your best line of defense is to remove poisonous plants from your landscape or at least fence them out of reach.


Manoguerra suggests making a map of your yard and identifying all of the plants. When you run across a plant you can’t identify, take a snapshot or a cutting to a nursery that has certified nursery personnel and ask for assistance.

Before adding any new plants to your yard, research them to make sure they aren’t toxic.

Because certain mushrooms are highly toxic, pull up any mushrooms and throw them away immediately.

And, because accidents often happen away from home, inspect any house you are visiting for poisonous plants.

Plant Poisoning in Animals

Poisonous plants are risky to pets too, as are certain plants that are nontoxic to humans such as onion, garlic, avocado, aloe vera and apple (seeds).

“People are often surprised that so many plants are toxic to pets,” said Jill Richardson, a veterinary poison information specialist with the Illinois-based ASPCA Animal Poison Control Center.

The most common call they receive is about lilies, which can cause acute renal failure in cats. “I advise cat owners to not have lilies in the house or yard because one bite is all it takes and the symptoms are gradual,” she said. “We usually don’t get the call until three days later, at which point the cat is in kidney failure.”


Orange Veterinarian Jeff Horner of Orange Veterinary Hospital has seen death caused by oleander and ‘Yesterday, Today and Tomorrow’ (Brunfelsia).

If you suspect that your pet has ingested a poisonous plant, bring the pet and the suspected plant to the vet. “Although we’re not botanists, seeing the plant can sometimes help us make an accurate diagnosis,” Horner said.

* The San Diego Division of the California Poison Control System, which serves Orange County, can be reached at (800) 876-4766. For additional information, including lists of toxic and nontoxic plants, visit

* The ASPCA Animal Poison Control Center can be reached at (888) 426-4435 or (800) 548-2423. There is usually a charge for help with a poisoned animal. For additional information, visit the Web site at


Plants to Watch Out For

Highly Toxic

Some plants have foliage, flowers or fruit that can be highly toxic when eaten. For a list of plants toxic to animals, call the Orange Veterinary Hospital at (714) 978-6260 or visit the ASPCA National Animal Poison Control Center’s Web site at Here is a list of plants that are known to be deadly to humans:

* Angel’s trumpet (Brugmansia)

* Azalea

* Carolina jessamine (Gelsemium sempervirens)

* Castor bean (Ricinus communis)

* Cestrum spp.

* Daphne

* Delphinium

* Echium vulgare

* Foxglove

* Heliotrope

* Jimson weed (Datura stramonium)

* Larkspur

* Lily-of-the-valley

* Lobelia

* Lupine

* Meadow saffron (Colchicum autumnale)

* Morning glory (seeds)

* Myoporum

* Nicotiana spp.

* Oleander

* Poison hemlock (Conium maculatum)

* Pregnant onion (Ornithogalum)

* Scilla

* Sweet pea

* Yew (Taxus spp.)

Less Toxic

There are many common plants that have foliage, flowers or fruit capable of producing a wide range of problems in humans such as skin rashes, painful swelling of the mouth, vomiting and diarrhea. If eaten in large quantities, some of the following plants may also cause more serious poisoning. This is not a complete list.


* Agave species

* Amaryllis

* Anemone

* Anthurium

* Arrowhead plant (Syngonium podophyllum)

* Birch tree (Betula species)

* Bird of paradise (Caesalpinia gilliesii)

* Boston ivy

* Caladium

* Calla lily

* Camphor tree

* Carnation

* Clematis

* Columbine

* Cotoneaster

* Croton

* Cyclamen

* Daffodil

* Dieffenbachia

* Elephant’s ear (Alocasia/Colocasia)

* English ivy (Hedera spp.)

* Eucalyptus

* Euonymus

* Euphorbia species

* Four o’clock (Mirabilis jalapa)

* Gladiolus

* Holly (berries)

* Hyacinth

* Hydrangea

* Iris

* Jatropha

* Jerusalem cherry (Solanum pseudocapsicum)

* Kaffir lily (Clivia spp.)

* Love-in-a-mist (Nigella damascena)

* Ming aralia (Polyscias spp.)

* Mistletoe

* Mum

* Narcissus

* Peace lily (Spathiphyllum)

* Philodendron

* Pokeweed (Phytolacca americana)

* Poppy

* Potato (green parts)

* Pothos (Epipremnum aureum)

* Primrose

* Privet (Ligustrum)

* Pyracantha spp.

* Rhubarb (leaves)

* Rubber plant (Ficus spp.)

* Sago palm

* Sansevieria

* Schefflera

* Snowflake (Leucojum spp.)

* Tobacco

* Tomato vines

* Tree tobacco (Nicotiana glauca)

* Tulip

* Umbrella plant (Cyperus alternifolius)

* Wisteria (seeds)

* Yarrow