To be classified as poisonous, a plant simply needs to produce some type of adverse reaction when people are exposed to it. Many external allergic reactions account for some plants to be called poisonous. Some plants can also cause internal poisoning when ingested. The part of a plant that actually causes the reaction or poisoning is called a toxin. Unfortunately, that same plant may appear on lists that are classified both as safe and as poisonous.

One of the most dangerous aspects of dealing with poisonous plants is variability. Some people may react severely to poison ivy, while others could pitch a tent in the middle of a patch and not be bothered in the least. The same variability applies to many plants. To further complicate things, factors such as the time of year, the type of growing season and the level of maturity may affect the level of toxicity in a plant. The age, size and health of the person exposed may also influence toxicity.

The bottom line when dealing with a poisonous plant is to contact a poison control center if you have any doubts about a plant you, your children or pets are exposed to. In the meantime, before you have a potential problem, make it a point to find out about the plants sharing your life.

Guidelines to Prevent Poisoning

Do not eat any part of a plant that you cannot identify or if you are uncertain that it is safe.

Keep house plants out of the reach of children and pets.

Avoid landscape plants that are poisonous if you have children or pets.

Make a special effort to teach children about plants.

Store seeds and bulbs away from food preparation areas.

Keep a list of the plants in your landscape. Whenever possible, find out the botanical name as well as the common name.

Setting the Record Straight: Dealing with Common Misconceptions

Just because an animal eats a plant, it doesn't mean it's safe for humans. For instance, furry creatures are rarely bothered by poison ivy. The opposite is also true. Plants that are safe for humans may be toxic to animals. For more information call the animal poison control center at 612-337-PETS.

Even if a plant has traditionally been used in teas and medicines, it may not be safe. We are now learning about the possible side effects of plants we thought to be safe or even curative, for centuries. For instance, comfrey is now being investigated as a possible carcinogen.

It used to be said that cooking will destroy toxins, but this is not always true. For example, young pokeweed greens have been traditionally eaten by boiling them, pouring off the tainted water, adding fresh water and repeating the process several times. Yet mature foliage, roots or berries of the plant can be very toxic whether cooked or not. Elderberries can be used in jams when cooked, but may make you ill if eaten fresh.

Any mushrooms that grow in your yard should be considered poisonous. There are many risks involved in trying to distinguish the different types of mushrooms.

Just because it is safe for humans, does not mean it is safe for animals. Even though some people have dogs who love chocolate, too much can be toxic.

You cannot always safely dispose of poisonous plants by burning or composting. The toxins might become part of the smoke and be inhaled.

Just because one part of a plant is safe, it doesn't mean the whole plant is safe. Tomatoes are a perfect example. The fruit is the only edible part of the plant. Rhubarb stems are edible and rhubarb leaves are toxic. Apricot fruits are edible, but their seeds are poisonous.

Being able to handle something toxic without a reaction doesn't mean it can be safely ingested. Aloe may be great for soothing burned skin, but when eaten, it can be a powerfully painful laxative.

The amount of exposure can determine if a plant is poisonous. Licorice is a great flavoring for foods and candies but used in excess, it can cause problems for the heart and kidneys.

Poinsettia
Widely thought to be poisonous, this plant is, at most, a skin irritant. It is part of the Euphorbia family. It produces a milky, sticky sap that can result in a rash. Tests have shown that an average child would have to eat a bowlful of colored bracts (leaves) before showing any effect. Since they don't taste good, that is very unlikely. If a skin irritation occurs, or if you are concerned, call a physician or the poison control center immediately.

Common Plants with Poisonous Properties -(Some are only mildly toxic, others are dangerous)

Garden Annuals - Perennials
Moonflower Datura
Monkshood Aconitum
Bleeding Heart Dicentra
Castor Beans Ricinus
Foxglove Digitalis
Lantana Lantana
Delphinum Delphinium
Lupines Lupinus
Sweet Pea Lathyrus
Tansy Tanacetum
Lobelia Lobelia
Poppies Papaver
Morning Glory Ipomea

Wild/Native/Volunteers
Poison Ivy Toxicodendron
Creeping Charlie Glechoma
Elderberry Sambucus
Jimsonweed Datura
Milkweed Aesclepias
Mushrooms
Nightshade Solanum
Hemlock Cicuta and Conium
Pokeweed Phytolacca
Sumac Rhus
Baneberry Actaea

Landscape Plants
Rhododendron Rhododendron
Azaleas Rhododendron
Buckeyes Aesculus
Arborvitae Thuja
Barberry Berberis
Buckthorn Rhamnus
Cotoneaster Cotoneaster
Sumac Rhus
Yew Taxus
Daphne Daphne
Bittersweet Celastrus
Wisteria Wisteria
Clematis Clematis

Indoor Plants
Dieffenbachia Dieffenbachia
Ivy Hedera
Jersusalem Cherry Solanum
Oleander Nerium
Azalea Rhododendron
Bird of Paradise Strelitzia
Crown of Thorns Euphorbia
Cyclamen Cyclamen
Eucalyptus Eucalyptus
Mistletoe Phoradendron
Philodendron Philodendron
Rosary Vine Ceropegia
Primrose Primula

Bulbs, Tubers, etc.
Iris Iris
Caladiums Caladium
Daffodils Narcissus
Hyacinths Hyacinthus
Fall Crocus Colchicum
Elephant Ears Colocasia
Lily of the Valley Convallaria
Snowdrops Galanthus
Amaryllis Hippeastrum

 For more information or in case of emergency, contact your local poison control center or physician.