Houseplants are often used to dress up the interior of a room, office or other indoor space. Many work to remove toxins from the air even as they add oxygen. But some houseplants contain chemicals that make them toxic to humans and pets if consumed and, in some cases, if the plant makes contact with the skin. For these reasons, it is important to know the toxicity of a plant before you put one in your home.
Houseplants range widely in their toxicity. Some are completely harmless to both pets and humans, such as the popular Boston fern (Nephrolepis exaltata). Others are poisonous to only pets, or even dogs but not cats. Still others have poisonous parts, such as the seeds, but are otherwise nontoxic. In a few isolated cases, a houseplant may be deadly to humans, such as in the case of oleander (Nerium oldeander).
Most poisonous plants contain a combination of toxins that affect different parts of the body. Many have sap that causes dermatitis, or irritation of the skin. If a toxic plant that contains glycosides is consumed, the heart rate may speed up and the gastrointestinal tract may become irritated. Some plants contain oxalates, which cause pain in the mouth and stomach. Solanine is another toxin found in some houseplants that causes vomiting, weakness and possibly loss of consciousness, according to the University of Nebraska. Plants that are highly toxic contain cardiac glycosides, which can cause death if consumed.
Toxic to Humans
Highly toxic plants should not be used indoors if there are children or pets present, warns the University of Connecticut. Many of these plants, if ingested, will attack the heart, brain or central nervous system, causing convulsions, permanent injury and even death. Such highly toxic plants include all parts of oleander (Nerium oleander), the seeds of the sago palm (Cycas revoluta) and the cardboard palm (Zamia sp.).
Moderately toxic houseplants are more common than deadly indoor plants. Moderately toxic plants, if consumed, usually cause pain, vomiting, diarrhea, and possible kidney problems. Such plants include the bulb of the amaryllis (Hippeastrum sp.), all parts of daffodils (Narcissus sp.) and the leaves and berries of holly (Ilex sp.).
Some plants are mildly toxic. These plants contain sap or juices that may cause an allergic reaction on the skin. The popular anthurium plant is one that many home gardeners are allergic to. Many are also allergic to the peace lily (Spathiphyllum sp.).
Poisonous for Pets
Easter lilies (Lilium longiflorum) can be fatal to pets, according to Denver Plants, and should not be placed near where curious cats can nibble on them. Alocasia, or elephant's ear, is frequently grown indoors for its foliage and is toxic to both dogs and cats. Aloe plants are known for their healing properties, but all parts of the plant are toxic to dogs and cats if ingested.
Safe for Everyone
Many plants are perfectly safe for all members of the family, human or furry. Phyllostachys aurea, or golden bamboo, is nontoxic, according to the University of Connecticut. So is the Christmas cactus (Schlumbergera bridgesii), which is often given as a gift, and the colorful coleus hybrids. All species of the hardy draceana plants are also nontoxic.