Linda Crampton is a writer and experienced science teacher with an honors degree in biology. She enjoys writing about science and nature.
The Benefits and Dangers of Indoor Plants
Indoor plants are a wonderful addition to a home and have many benefits. They are lovely to see and often improve the appearance of a room. Plants such as herbs are edible and may be medicinal as well. Learning how to take care of houseplants teaches children responsibility and may arouse their interest in gardening, which can be a lifelong joy. Having plants in a home is also a great way to connect with nature.
It's important that everyone in the family knows about any dangers associated with plants brought into the home. While many common houseplants are safe, some are poisonous for people and/or pets. This may not be a problem in a home with only adults and older children. If young children or pets live in the home, it's a good idea to avoid plants that are even mildly toxic.
Research Plant Safety Before You Buy
This article describes twelve common houseplants that are poisonous to humans and pets, symptoms of poisoning to look out for, and examples of safe alternatives. Some additional plants that may be kept in homes are also poisonous. The safety of a houseplant should be investigated before it's bought.
12 Common Houseplants That Are Poisonous
|Plant||Symptoms of Poisoning||Safe Alternative|
Ingestion can cause stinging or burning of mouth and throat. It can also cause soft tissue to tear and become inflamed.
Variegated baby rubber plant, prayer plant, or cast iron plant
Similar to dieffenbachia poisoning
Variegated baby rubber plant or prayer plant
Similar to dieffenbachia poisoning
Baby rubber plant, prayer plant, areca palm, or parlour palm
Similar to dieffenbachia poisoning
5. Peace Lily (Spathe)
Similar to dieffenbachia poisoning; contact with the sap can cause skin irritations
African violet, wax plant, or moth orchid
6. Calla Lily
Similar to dieffenbachia poisoning but milder
African violet, moth orchid, or Barberton daisy
Extremely toxic; possible symptoms of ingestion include a severe rash, nausea, vomiting, dizziness, heart problems, and seizures
African violet, wax plant, moth orchid, or Barberton daisy
Ingestion of the bulbs can cause mouth and throat irritation, nausea, vomiting, and diarrhea. Frequent contact with the skin can lead to dermatitis.
Ingestion of the bulbs can cause mouth and throat irritation, nausea, vomiting, and diarrhea.
Pot marigold (Calendula)
Ingestion of the bulbs can cause symptoms similar to ingestion of hyacinth bulbs. Frequent contact with the bulbs can lead to dermatitis—particularly in people with sensitive skin.
African violet, pot marigold, or Barberton daisy
11. English Ivy
Contact with ivy leaves can cause the skin to redden, itch, and blister. Ingestion can cause fevers, difficulty breathing, delirium, and convulsions.
12. Snake Plant
Extremely toxic to pets; symptoms are often mild in humans and include mouth and throat irritation, nausea, and vomiting
Cast iron plant
1. Dieffenbachia (Dumb Cane)
Dieffenbachia, or dumb cane, is a tropical plant that is native to Central and South America. It's popular as a houseplant because of its large and attractive leaves. The leaves are green with light yellow or cream blotches arranged in a variety of patterns. The stems are thick and resemble canes.
The word "dieffenbachia" is used as both a genus name and a common one. (The genus is the first word in the scientific name.) The plant is a relative of the North American skunk cabbages and belongs to the family Araceae. As in a skunk cabbage, a dieffenbachia's small flowers are born on a long, rod-like structure called a spadix that is partly enclosed by a sheath called a spathe. This type of inflorescence (clustering of flowers) is characteristic of the Araceae.
What Makes Dieffenbachia Poisonous?
All parts of a dieffenbachia contain raphides, which are needle-shaped crystals of calcium oxalate. Raphides cause stinging and burning sensations in the lips, mouth, tongue, and digestive tract. They can also cause tears in soft tissue, leading to inflammation and swelling that can prevent speech (hence, "dumb cane"). In more serious cases, raphides can block the airways and interfere with breathing.
The skin may develop a rash and an itch after exposure to the plant's sap. Contact with the eyes can damage the cornea—the outer layer of the eye—and cause extreme pain. It's a good idea to wear gloves when handling the plant. Ingestion of the plant may cause nausea, vomiting, and diarrhea.
Raphides occur in other plants as well and are thought to protect them from herbivores. Researchers believe that a dieffenbachia contains other toxins in addition to calcium oxalate.
What Do You Do If You Accidentally Ingest the Plant?
According to the NIH (National Institutes of Health), if someone has chewed or eaten part of a dieffenbachia plant, their mouth should be washed with a cold, wet cloth. They should also be given milk to drink, and a poison control center should be contacted.
If someone is unconscious or unable to swallow, they must never be given anything by mouth. The hands and eyes of the injured person must also be washed if these body parts have contacted the poison.
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Usually, the damage done by Dieffenbachia is unpleasant but not serious. The discomfort in the mouth may be severe and last for days, however. Fatalities have occurred from dieffenbachia poisoning, but they are very rare.
What Are Safe Alternatives for Dieffenbachia?
If the intriguing patterns on the leaves are what you're after, then consider a variegated baby rubber plant (Peperomia obtusifolia) or a prayer plant (Maranta leuconeura). Their leaves are smaller than a dieffenbachia's, but they are non-toxic and are safe around pets and children.
If you're looking for a plant with large leaves, you may find the cast-iron plant (Aspidistra elatior) to your liking. Although not as broad or showy as the dieffenbachia's, the cast-iron plant's leaves are long. The plant is also easy to care for and doesn't require much light or water.
Twelve Plants That Contain Raphides
|Common Name||Scientific Name|
Swiss Cheese Plant
As in the case of a dieffenbachia, the word "caladium" is both a genus and a common name. Multiple types of caladiums exist. Different types have different leaf patterns. The arrow-shaped leaves are generally variegated (having more than one color, usually in patches or other patterns) and contain different pigments, including green, yellow, pink, red, or brown. The plants are a part of the family Araceae.
Caladiums can be grown in a container indoors or outdoors and also grow well in a garden. The leaves are beautiful and may become very large, prompting the moniker "elephant ear"—a name that is applied to several other plants as well. They have also been beautifully dubbed "angel wings".
What Makes Caladium Poisonous?
Like other plants in the Araceae family, caladiums contain raphides that cause symptoms similar to those of dieffenbachia poisoning. Again, although they aren't particularly poisonous for adults (a large amount of the plant needs to be eaten before symptoms appear), they can be very toxic for young children and pets.
What Do You Do If You Accidentally Ingest the Plant?
If you, your child, or your pet accidentally chew or ingest part of a caladium, as with a dieffenbachia, clean the areas of contact with a cold and wet cloth and drink milk or water. When in doubt, call poison control or your veterinarian.
What Are Safe Alternatives to Caladiums?
Again, the variegated baby rubber plant or the prayer plant make great alternatives because of their intriguing leaf patterns and safety, although their leaves are smaller.
There are many different species in the genus Philodendron, and many of these are kept as indoor plants. Philodendrons have a wide variety of interesting leaf shapes and color patterns. They can be so different from one another that it's sometimes hard to believe they all belong to the same genus. Many philodendrons are climbers and produce aerial roots, while others don't climb.
What Makes Philodendron Poisonous?
Raphides are the culprit again. However, the evidence suggests that philodendron is only mildly poisonous and that most people have to eat a large quantity of the plant before they develop symptoms. Still, small children and pets are highly susceptible to poisoning by chewing or accidentally ingesting these plants. First aid protocols are similar to that in dieffenbachia and caladium poisoning.
What Are Safe Alternatives to Philodendrons?
Unfortunately, most other ornamental house plants with large leaves are also poisonous to humans and/or pets. Depending on what you're going for, good choices for intriguing leaf patterns are the baby rubber plant and prayer plant—both of which are safe for children, dogs, and cats.
If you want something similar to the split leaves depicted in the philodendron above, check out either the areca palm (Dypsis lutescens) or the parlour palm (Chamaedorea elegans). The latter is especially good for those looking for a low-maintenance indoor plant.
4. Pothos (Devil's Ivy)
Pothos (genus Epipremnum) is another popular houseplant. It's an evergreen vine that trails over the edge of its container. The plant is attractive and doesn't require much attention, which is why it's popular in public areas such as shopping centers and offices. Many species exist. They have a variety of leaf colors and patterns. Some have solid green leaves, while others have variegated leaves. The leaves are usually heart-shaped with pointed tips.
Pothos and some types of philodendrons are often confused with one other. If someone wants to make sure that they are buying a pothos instead of a philodendron, or the other way round, they should visit a nursery or garden store with knowledgeable and experienced staff.
What Makes Pothos Poisonous?
The calcium oxalate crystals cause the same irritating symptoms as dieffenbachias, caladiums, and philodendrons. Although they are classified as only mildly to moderately toxic, to a small child or pet, they can be extremely toxic. As mentioned previously, the severity also depends on how much is ingested. First aid protocols are the same as for ingestion of dieffenbachias, caladiums, and philodendrons.
What's a Safe Alternative to Devil's Ivy?
Swedish ivy (Plectranthus verticillatus) also grows as a vine and is often seen draping over hanging baskets in shopping centers. What's great is that unlike other ivy varieties, the Swedish ivy is safe for children, dogs, and cats.
5. Peace Lily (Spathe)
Despite its name, the peace lily, or spathe, isn't a true lily. It belongs to the genus Spathiphyllum, which is part of the family Araceae. The leaves of the peace lily are long, narrow, and have a pointed tip. They feel leathery, are dark green in color, and have a shiny surface with prominent veins.
The inflorescence has a white or light green spathe and is borne on a stalk that extends above the rest of the plant, resembling flags of surrender or peace. This is the reason why the peace lily was given its name.
What Makes the Peace Lily Poisonous?
Like its relatives above, the peace lily contains calcium oxalate crystals and can produce unpleasant symptoms if accidentally ingested or if liquid from the plant contacts the skin.
What's a Non-Poisonous Alternative to the Peace Lily?
Although more vine-like than the peace lily, the wax plant (Hoya) produces round clusters of small, white, and fragrant flowers and is safe for both humans and pets. If you're looking for a flower that is more prominent, the moth orchid (Phalaenopsis) should suit you well. The tall and exotic flowers resemble moths' wings and come in many different colors and patterns. The plant is also one of the hardiest orchids.
6. Calla Lily
The calla lily (Zantedeschia aethiopica) is native to Southern Africa. Like the peace lily, the calla lily isn't a true lily (family Liliaceae) but is a member of the family Araceae.
The large and beautiful white "petal" of the calla lily is actually a spathe, a bract (modified leaf) that surrounds the flower cluster of the plant. It surrounds a yellow, orange, or pink spadix, a spike where the small flowers are located. The spathe is uniquely shaped and has graceful curves that give it an elegant appearance.
What Makes the Calla Lily Poisonous?
The calla lily is yet another plant that contains calcium oxalate crystals. It's only mildly poisonous, which is good news for people who would like to bring this beautiful plant into their home. However, people with small children and pets should still stay clear.
What's a Non-Poisonous Alternative to the Calla Lily?
Although the characteristic white spathe is irreplaceable, the African violet (Saintpaulia), moth orchid (Phalaenopsis), and Barberton Daisy (Gerbera jamesonii) are all non-toxic and offer colorful and exotic flowers.
Lily Poisoning in Cats
So far, I've described the toxicity of plants mostly in terms of how they affect humans. Although the toxins can cause similar symptoms in cats and dogs, this isn't always the case. Pet owners should do some diligent research before they bring a plant into their home.
An example of the different effects of a plant poison in humans and pets is a toxin that's present in lilies. All parts of true lilies are non-toxic for humans but are deadly for cats. An unidentified chemical in the plant causes kidney damage in the animals, which is often fatal.
Symptoms of Lily Poisoning Include:
- loss of appetite
What to Do If You Suspect Lily Poisoning
It's very important that vet treatment is sought as soon as possible after a cat eats any part of a lily. The longer the time between ingestion and treatment, the less likely that the cat will survive. Signs of lily ingestion can also be signs of other illnesses. If a cat has had access to lilies, however, lily poisoning must always be considered as a cause of the symptoms.
All pet owners should know where their nearest animal emergency clinic is located as well as the hours when the clinic is open. They should also think about their transport method to the clinic. Public transit is rarely suitable in an emergency.
Prevention Is Best
Preventing lily poisoning is much easier than treating it. Avoid planting lilies in indoor pots or having lily bouquets where your cat can access them. I have three cats and would never bring a lily into my home.
Oleander (Nerium oleander) is beautiful but extremely toxic—even in small amounts. It's an evergreen flowering shrub that is grown both outdoors and indoors and produces flowers that can be pink, red, purple, or white. The leathery leaves are long and narrow and have a pointed tip. They are often arranged in pairs or whorls on the stem.
What Makes Oleanders Poisonous?
Known toxins in oleander include oleandrin, oleondroside, neriin, and digitoxigenin. The toxins are present in all parts of the plant. Even the flower nectar of oleander and the honey that bees make from the nectar contain a dangerous amount of poison.
The list of symptoms caused by oleander ingestion is long, but it can be broken down into categories based on the system affected. Note that not all of the symptoms may appear, and they may be caused by a different problem. However, if oleander poisoning is suspected, seek emergency help right away as the condition could be very serious.
- stomach pain
- blurred vision
- halos in the visual field
- a rash
- a slow or irregular heartbeat
- low blood pressure
Nervous System Problems
- loss of consciousness
Oleander poisoning is a medical emergency. Treatment by a medical professional is essential.
What's a Non-Toxic Alternative to Oleander?
The wax plant, moth orchid, Barberton daisy, and African violet all produce beautiful, non-poisonous flowers that are safe for both pets and humans.
8. Daffodil (Narcissus)
Daffodils belong to the genus Narcissus. Other members of this genus are also sold as houseplants and can cause the same health problems.
What Makes Daffodils Poisonous?
Daffodil bulbs contain calcium oxalate crystals and a toxic alkaloid called lycorine. Eating the bulb can cause oral irritation, upset stomach, nausea, vomiting, and diarrhea. In addition, people who frequently handle the bulbs may develop dermatitis, a condition in which the skin becomes inflamed, red, and itchy.
Daffodil bulbs are sometimes mistaken for edible bulbs, such as onions. An instance of this mistaken identity occurred in an English elementary school in 2009. Onion bulbs were collected from a school garden to add to soup that the children were making. Somehow, a daffodil bulb became mixed with the onion bulbs. Twelve children developed stomach cramps and vomiting after eating the soup and were taken to hospital. Thankfully, they were all able to recover.
What's a Non-Toxic Alternative to Daffodils?
The African violet (Saintpaulia) is safe for children and pets and has beautiful, velvety flowers.
Hyacinths come in two common versions: the common hyacinth (Hyacinthus) and the grape hyacinth (Muscari). Both are bulbous plants that produce flowers that are violet, white, or pink. The main difference can be noticed in mid-spring, when the flowers bloom. Common hyacinth flowers bloom outward into a star shape, while grape hyacinth flowers (as the name suggests) have a closed bloom such that the flowers resemble bunches of grapes.
What Makes Hyacinths Poisonous?
Like daffodils, hyacinths contain calcium oxalate and lycorine. Once again the toxin is most concentrated in the bulbs of the plant. Eating hyacinth bulbs produces the same symptoms as eating daffodil bulbs.
What's a Non-Toxic Alternative to Hyacinths?
Some species of marigolds, like the pot marigold (Calendula) are safe for humans and pets, while other species, like the French or African marigold (Tagetes spp.) are mildly poisonous to dogs and cats if ingested or touched. If you are getting marigolds, make sure they are from the genus Calendula and do some research to be safe.
Tulips (genus Tulipa) are a popular, bulbiferous, and spring-blooming flower. There are over 3,000 types of tulips. The most common colors seen include white, yellow, orange, pink, red, blue, and purple. Tulips can instantly brighten a landscape and are often seen in large garden beds, in bunches along walkways, in pots both indoors and outdoors, or arranged in vases as a decorative piece.
What Makes Tulips Poisonous?
The bulbs contain a toxin called tuliposide A that can cause dermatitis in humans, but apparently only in people who are sensitive to the toxin. People who frequently handle the bulbs are most susceptible to the dermatitis. Tulips also contain calcium oxalate. Eating large amounts of tulip bulbs may cause mouth and throat irritation, excess drooling, nausea, and diarrhea.
Although tulip bulbs have sometimes been eaten after they have been prepared in a specific way, they are often considered to be poisonous. They may be especially toxic for people that are sensitive or allergic to tulips. For dogs and cats, tulips are considered highly toxic when ingested in large amounts.
What's a Non-Toxic Alternative to Tulips?
If you're looking for a pet-safe flower to decorate your home, consider the African violet, pot marigold, or Barberton daisy.
11. English Ivy
English ivy (Hedera helix) is a climbing and trailing vine. Cultivated ivy is sold with both solid green leaves and variegated leaves. Leaves on the climbing stems have pointed lobes. The leaves on flowering stems are oval. English ivy is an attractive plant, but in the wild, it can become invasive.
What Makes English Ivy Poisonous?
The liquid from a damaged ivy plant can severely irritate the skin and cause dermatitis. After handling ivy, a person may find that their skin is itching, red, and blistered. The plant can also cause very serious internal problems, although generally many leaves must be eaten to cause these effects. A person may develop a fever and experience breathing difficulties, vomiting, delirium, hallucinations, and convulsions.
What's a Non-Toxic Alternative to English Ivy?
If you're looking for non-poisonous hanging plants, consider the baby rubber plant, Swedish ivy, prayer plant, or the succulent alternative: donkey's tail or burro's tail.
12. Snake Plant (Mother-in-Law's Tongue)
The snake plant is attractive and has upright leaves. Those of some varieties are green bordered by yellow, as shown in the photos in this article. About seventy varieties of the plant exist. Their leaves have slightly different shapes, patterns, and shades. Unfortunately, they are toxic. The snake plant's relative in the genus Sansevieria, the viper's bowstring hemp, is also considered to be toxic to humans and pets.
What Makes the Snake Plant Poisonous?
All parts of the snake plant are poisonous, thanks to the presence of saponins. These chemicals can cause gastrointestinal discomfort as well as nausea, vomiting, and diarrhea in humans and pets, although the symptoms are much milder for humans.
What's a Non-Toxic Alternative to the Snake Plant?
A safer alternative that also features large, prominent leaves is the cast iron plant. This plant has the added benefit of being very low-maintenance. It can tolerate low lighting, humidity, and minimal watering.
Can the Plant Remove Air Pollutants?
NASA researchers have discovered that the snake plant and some other plants can remove volatile organic chemicals (VOCs) from the air. Other researchers have concluded that some of the plants that they tested can do the same thing. However, investigators who analyzed the research say that most of the experiments were performed with relatively small and sealed plant chambers and that the results don’t necessarily apply to an entire room or a home. It seems as though more studies are necessary.
Someone who wants to bring a snake plant into their home should consider its safety profile with respect to the individuals (both human and non-human) who live in the home instead of its possible effect on air pollution.
Effects of Plant Poisons
Any plant that's classified as poisonous needs to be treated with care, even if it's only mildly toxic. The health effects of a plant toxin depend on many factors, including:
- the nature of the toxin
- the part of the plant that's eaten
- how much toxin is in the plant
- how much of the plant is ingested
- the length of time that the person is exposed to the toxin
- the body mass of the person who has eaten the plant
- the overall health of the person at the time of ingestion
- the individual sensitivity of the person to the toxin
Houseplant Benefits and More Safe Types
I love my pets and also enjoy having houseplants in my home. The plants are attractive and interesting to examine. Supporting their health, growth, and flower production can be a rewarding activity. Though they don't respond to my attention exactly as my pets do, the fact that they are living organisms make them a valuable addition to my home.