Sept. 17, 2009 -- They're beautiful to look at and can help improve air quality, but some of the most prized house plants harbor some potentially harmful toxins.
As the weather turns chilly and you bring your plants indoors, bear in mind that some ornamental plants, if ingested in large enough quantities, can be poisonous to small children and pets.
The most likely victims, experts say, are children under 3 years old and smaller pets. Usually, smaller bodies are affected by smaller amounts of toxin.
"You bring that plant indoors and all of a sudden it's a toy for the black lab. Or kids see berries on the floor and pick them up," said Dr. Krenzelok, director of the Pittsburgh Poison Control Center and a professor at the University of Pittsburgh.
For decades, he said, plants ranked as the fourth most common type of poisoning exposure in children. The most recent data compiled by the American Association of Poison Control Centers shows that it's dropped to ninth, though he couldn't explain why.
He emphasized that in most cases, a negative reaction won't occur unless a significant amount of the plant is ingested. But he urged people to call 1-800-222-1222 to reach a local poison control center if they are concerned.
National Gardening Association senior horticulturist Charlie Nardozzi also stressed that he wouldn't discourage people from keeping these plants. "You just have to use some common sense with them," he said.
Keeping the plants out of reach of small children and pets and picking up fallen leaves and berries is most likely enough to ensure safety.
Here are nine plants to handle with care.
Green, leafy and fairly low maintenance, philodendrons are among the more popular house plants. But though their durability makes them easy to care for, they also contain a toxin in their leaves called calcium oxalate. If ingested by pets or children, they could cause inflammation of the mucus membranes in the mouth and throat.
Krenzelok said he doesn't discourage people from keeping them in the house as the reaction is unlikely to be severe. However, he said it might be wise to keep them out of reach of children.
In the same family as philodendrons (the Araceae family), caladiums, or elephant ears, are also considered beautiful houseplants. But like their greener sibling, they also contain calcium oxalate and can irritate the mouth and throat.
According to the National Institutes of Health, if too much of the plant is ingested, the mouth and tongue can swell. Nausea, vomiting and diarrhea are also possible symptoms.
Pretty but Potentially Poisonous Plants
Krenzelok said if a child picks up and chews fallen leaves, he or she could get an upset stomach. If eaten by a child, he advises parents to take it out of his or her mouth and then rinse out the child's mouth.
Flowering plants that sometimes resemble pom-pons, hydrangeas bloom from early spring to late autumn. But the plants, that can also come indoors in the colder months, contain a cyanide-like compound. Krenzelok said he's never seen a case of hydrangea poisoning, but said, if ingested, they could potentially make someone ill.
With thin green leaves and tiny red berries, the Jerusalem Cherry plant is festive plant to have around the house in the fall and winter. But those bright-colored berries could attract the attention of a small child and, though experts say they're not fatal, if swallowed, they could give a child abdominal pains and headaches.
They also say the toxin responsible for the reaction, solanine, could also negatively effect pets if eaten in large enough quantities.
A flowering shrub mostly used as a landscaping plant, azaleas are a favorite among plant enthusiasts and are occasionally brought indoors.
However, grayantoxins in the leaves that can be harmful if ingested in large enough amounts. Krenzelok said casual exposure by a small child isn't a significant concern but said he's seen problems when people have tried to make tea from the leaves.
Thinking they're making a tea with medicinal properties, they pick the leaves and mix them with boiling water. But, he said, they basically become ill because they extract the toxins.
Azaleas can also produce vomiting, diarrhea and other symptoms in animals. Severe cases could lead to coma and death from cardiovascular collapse, according to the American Society for the Prevention of Cruelty to Animals.
Some Festive Plants Can Be Harmful
Especially popular around the Easter holiday, the Easter Lilies can also be kept as house plants. But though they spruce up a home, they are also considered highly toxic to cats, potentially causing kidney failure.
According to the University of Pennsylvania's School of Veterinary Medicine, ingesting any part of the plant could cause a cat to vomit, lose its appetite or become lethargic within a few hours.
Nearly as ubiquitous as wreaths around Christmas time, poinsettias have a lethal reputation. But, contrary to folklore, toxicologists say ingesting part of the poinsettia plant will not kill you. "It does not deserve the reputation that it has," said Krenzelok.
Skin contact with the plant's milky sap could result in an allergic reaction and nausea could ensue if swallowed, but he said the consequences are not as bad as many believe.
A flowering plant that grows in many colors, the oleander is often seen as an outdoor plant in warmer areas. But Charlie Nardozzi said it can also be an indoor plant.
If you decide to bring it indoors, however, bear in mind that the plant is considered among the more poisonous.
Nardozzi said ingesting some of the leaves could be fatal to a small child or pet.
Krenzelok said it has the potential to be hazardous but unless a significant amount is consumed it's unlikely to cause any problems.