Which Indoor Plants Are Poisonous

Placing indoor plants inside your office and home has many good benefits for your health. They are a good addition to your decor, can help in improving your mood and also purify toxins from the air.  Their beautiful appearance adds a pop of color in a given space. They also serve as a wonderful centerpiece on a table arrangement and can be very eye pleasing when arranged properly.

However, owning indoor plants means that you have to fully understand their needs through their different characteristics. It is also important to know that some of the indoor plants on sale have some unfavorable trait, like being poisonous to you, your pets and your kids.

Some unsuspecting plants that can be poisonous or harmful are: Oleander, Lily of the Valley, and Golden Pothos. Read on to discover why these, and many other, seemingly harmless plants can be harmful, and how to safely handle and care for them.

Why are some indoor plants poisonous?

Some indoor plants are poisonous because this is their way of protecting themselves from herbivores when they are in their natural environment. Through the process of evolution, many plants have developed ways on how they can deter animals from eating them. There are physical developments such as spines, prickles, and thorns. The most common protection for plants is their ability to produce chemical compounds that are poisonous.

So, be careful of those beautiful indoor plants you own. You might be already harboring these poisonous ones without you knowing.

Related: Find out which plants remove Co2.

Common Poisons found in Plants

Now that you know that there are indoor plants that are poisonous, the next step would be to know and understand the most common poisons found in plants.

Essential Oils: Common Poisons found in Plants

Essential Oils

There are some plants that produce essential oils that can be used for aromatherapy. On the other hand, there are essential oils in plants that are poisonous for pets, kids and adults. They can be extracted from different parts of the plants.


Plants that have the ability to produce essential oils have better odds in protecting themselves from funguses to ensure their survival in their natural elements. In some cases, essential oils produced by plants have the ability to poison others. It prevents neighboring plants to perform photosynthesis and germination.

Side Effects

The main organ that can be affected by essential oil poisoning is the liver. Infants and elder people with thin skin can also suffer from skin irritation when exposed. Other effects range from, allergic reaction, pneumonia, hallucinations, and in extreme cases seizures or coma.

Essential oils are great when used in small amounts. There are companies that sell essential oils as a possible alternative to anti-anxiety, anti-inflammatory, and anti-microbial medications. The proper dosage and usage of these oils play a vital role in preventing you and your family members from poisoning.

Alkaloids: Common Poisons found in Plants


This is a chemical compound mostly found in plants and can be considered poisonous when ingested in large amounts. Examples are morphine, ephedrine, and nicotine.


The role of alkaloids in plants is still unclear. There are suggestions that it is a waste product of the natural metabolic system of the plant.

Some studies have shown that there is a significant increase of this chemical in certain plants before seeds are formed and then drops when it is ready for harvest. Speculations have also said that this chemical compound is produced as a form of bug repellant by plants.

Side Effects

As you can see, the examples given above are samples of alkaloids that have beneficial effects on humans. Morphine is used as pain medication, ephedrine as anti-asthma and nicotine as a stimulant but all of these are only beneficial when used responsibly.

There are, however, alkaloids that pose a health threat to humans and animals. These poisonous alkaloids can cause hepatocyte necrosis that can lead to liver failure, jaundice, ascites, and death due to heart failure.

Non-Protein Amino Acids

Non-Protein Amino Acids

Amino acids are mostly found in plants that are consumed by both human and animals. However, some non-protein amino acids are found to be toxic to cattle and humans. If large quantities are present in one’s diet, the possibility of poisoning is very high.


Plants produce non-protein amino acids as a way to prevent herbivores from eating them in the wild. It is very difficult for plants to produce large amounts of poison because it takes up too much time and energy. Producing trace amounts of poisons that can cause discomfort to animals and prevents them from going back for seconds is more efficient.

Side Effects

There are many side-effects of ingesting non-protein amino acids and they range from as simple as headaches, nausea, diarrhea, and vomiting. The more serious side effects can be increased in blood pressure, hypoglycemia or low blood sugar, neurotransmission disruption, and protein synthesis inhibition. Without further treatment, this can lead to paralysis and death

Cyanogenic glycosides

This is a chemical compound that produces a highly toxic poison called hydrogen cyanide. This poison if more popularly called “cyanide”. Cyanide itself is not present in the plant but the chemical compound that produces it is.

Once this chemical compound undergoes a process called hydrolyzation; either through crushing, chewing, freezing or wilting, it releases the cyanide poison.


This is believed to be a defense mechanism developed through time, just like any plants that have a trace amount of poison in their system. Herbivores in the wild will suffer from cyanide poisoning the moment they ingest a plant with cyanogenic glycosides.

Side Effects

A well-known food called Cassava contains this compound and if not properly prepared or cooked, consumption of this can cause mild to severe poisoning. Mild poisoning side effects are nausea, vomiting, abdominal pain, and hyperventilation. In severe cases, respiratory failure, convulsion, paralysis which then leads to death can occur.

Cardioactive glycosides

More commonly referred to as cardiac glycosides are organic compounds present in plants that have the ability to increase the pump rate and force of the heart. This compound is mainly used for the treatment of congestive heart failure and cardiac arrhythmias. It is still not commonly used due to the toxicity level it has.


In ancient times, plants such as foxglove and milkweed are found in the forest. They have now become as ornamental plants in gardens and homes. Because of how beautiful they are, it is often forgotten that these plants have developed certain defense mechanism to protect them from their natural enemy.

These plants have been studied by experts and have found that a toxic compound called cardiac glycoside, which affects the heart is produced to defend themselves from herbivores.

Side Effects

Our ancestors have discovered this poisonous substance too. They have used it to coat their hunting arrows that induce a heart attack on their prey. Common symptoms are convulsions, hypertension, circulatory failure and anaphylactic reaction that may or may not lead to death.



This toxic chemical is found in plants under the Apiaceae, Moraceae, Rosaceae, Rutaceae, and Fabaceae family. They can be very toxic to both humans and animals.


Scientists have believed that the role of furanocoumarins is to protect the plant from pests, insects, and fungi. One of the most common plants that you can encounter that produce this chemical is the giant hogweed plant.

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Side Effects

Plants that contain this chemical compound can cause burning and stinging sensation on the exposed area, inflammation, blisters and burns may develop due to a phototoxic reaction called Phyto photodermatitis.



A chemical compound very commonly found in plants is saponin. It has a characteristic of producing a foamy soap-like substance when shaken in water.


This serves as an antifeedant that protects plants from fungi and microbes that may cause damage. It produces a bitter taste that animals don’t find enjoyable.

Side Effects

Humans rarely get poisoned by saponins. For saponin poisoning to happen, a large dose of the said chemical must be ingested or absorbed into the bloodstream. Watch out for gastrointestinal issues and also some vomiting, nausea and diarrhea. Pets are more susceptible to saponin poisoning than humans.


These can be characterized as calcium oxalate crystal that is shaped like needles. They are commonly found in indoor plants and can be very harmful to pets and inquisitive toddlers who put everything in their mouth.


Just like any other plant, this serves as a deterrent of the natural enemy of the plant. You also wouldn’t go back for more if you experience discomfort after eating it.

Side Effects

This can irritate the mouth, tongue, digestive tract and can produce a stinging and burning sensation. Severe cases can lead to tears in the soft tissues that will cause speech difficulty due to swelling.

Poisonous Plants and their symptoms when ingested by kids

Poisonous Plants and their symptoms when ingested by kids.

Plants have developed poisons as a way to help them survive in their natural habitat. Many of these plants are now part of the indoor plants that are being widely sold. Once you bring these plants indoors, you are subjecting your pets, kids and yourself into the possibility of being poisoned.

1. Oleander

This is a plant that thrives both indoor and outdoor. It is classified as a shrub and is very popular because of its beautiful flowers. All parts of it are considered poisonous and ingesting even a small amount can become fatal if not spotted immediately.

Oleander plant produces chemicals called oleandrin, oleondroside, neriin and digitoxigenin which are all poisonous to humans. Poisoning from this plant is an emergency situation and needs immediate medical attention and treatment.

Symptoms of Poisoning

Oleander poisoning can have many symptoms. These symptoms can also be due to other reasons. Ingesting this plant can cause the following:

  1. Vision problems such as blurred vision or seeing halos.
  2. Skin irritations like rashes and hives.
  3. It may also affect the gastrointestinal system which may cause all or some of these symptoms: stomach pain, nausea, vomiting, and diarrhea.
  4. Circulatory problems such as low blood pressure and irregular or slow heart rate
  5. The nervous system can also be affected. Watch out for headaches, drowsiness, confusions, dizziness, seizures, and unconsciousness.

2. Lily of Valley

This is a woodland flowering plant with very sweet-smelling blossoms. This is a very popular plant to bring indoors because of the fragrance its flowers produce. It is a very popular flower during weddings and is used to make perfume. Just like oleander, all parts of this plant are very poisonous. Kids and pets are advised to stay away from this plant.

This plant produces a toxic chemical compound called cardiac glycosides which affects the circulatory system.

Symptoms of Poisoning

A small amount of ingested can send anyone to the hospital. This plant contains thirty-eight different cardiac glycosides. Look out for symptoms such as:

  1. Abdominal pain
  2. Low blood pressure and slow heart rate
  3. Drowsiness
  4. Blurred vision
  5. Fluid from the plant may cause skin irritation and rashes if you came in contact with it.
  6. Vomiting
  7. Diarrhea

3. Golden Pothos

This plant is more commonly referred to as the devil’s ivy. It is a popular indoor plant that is dangerous to both kids and pets. Stems and leaves of this plant contain an insoluble toxic substance that can be very harmful when ingested.

Symptoms of Poisoning

The culprit behind the plant’s poisonous origin is a chemical called calcium oxalate. Upon chewing and biting this chemical can cause irritation and produce the following symptoms:

  1. Burning sensation in the mouth
  2. Swelling of tongue, lips, and throat.
  3. Labored breathing
  4. Swallowing problem
  5. Foaming in mouth
  6. Drooling
  7. Upset stomach and vomiting
  8. Diarrhea

4. Dieffenbachia

This is a Central and South America native plant and is mostly cultivated in pots that can be taken and displayed indoors. It has wide, bright and beautiful leaves that can really attract attention. It is also known as a dumb cane because of how its poison numbs the mouth.

Symptoms of Poisoning

All parts of this plant are poisonous due to a chemical compound called raphides. This compound has calcium oxalate crystals that are needle-shaped which causes tissue damage when swallowed.

  1. Burning and/or stinging of the mouth
  2. Inflammation of throat, lips, and tongue
  3. Rashes from sap exposure
  4. Numbness in mouth leading to a speech problem
  5. Nausea
  6. Vomiting
  7. Diarrhea
  8. Salivation

5. Philodendron

The different shapes of the leaves of this plant make it a popular choice for indoor plants. They are easy to grow and requires very little attention. Humans suffer very mild poisoning from ingesting these plants but kids are advised to stay away from this.

Symptoms of Poisoning

Like the previous plants, the culprit here are raphides present within the plant. You can refer to the lists of symptoms from the previous plant for this one.

6. Asparagus Fern

This is a very common indoor plant because of its soft and feathery leaves. Popularly used in flower decoration but is poisonous to pets and kids.

Symptoms of Poisoning

An organic toxic chemical compound called sapogenin is the reason behind its a poisonous trait. A large amount of sapogenin in the bloodstream can cause:

  1. Vomiting
  2. Diarrhea
  3. Stomach pain
  4. Skin irritation

7. Peyote

This is a member of the cactus family of plants. It is a native of the New Mexico and Texas region. It is mildly poisonous to adult humans but is categorized as moderately poisonous to kids and dogs.

Symptoms of Poisoning

The whole plant contains the alkaloid compound that is considered poisonous. Ingestion of this plant may or may not cause the following symptoms:

  1. Psychotropic symptoms such as confusion, irritable and mood swings
  2. Dizziness or nausea
  3. Vomiting
  4. Diarrhea

How can you tell when a plant is poisonous?

Prevention always is better than a cure. So, before you bring in a plant inside your office or home, look at the list below and use it as your checklist to determine if your plant is poisonous or not.

  • A poisonous plant usually has shiny leaves.
  • Plants with thorns are generally poisonous.
  • If your plant produces seeds inside a pod then it might be poisonous.
  • If the plant you own contains a milky looking sap.
  • Plants that have an umbrella shade structure are mostly poisonous.
  • Yellow and white berries producing plants might be poisonous.

These are just some guidelines that you can use if you want to identify poisonous plants inside your house or in your garden. Generally, this could also apply to wild plants in the forest and can greatly reduce the risk of getting plant poisoning during camping and other outdoor activities that can possibly expose you to such plants.

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The poisonous plants mentioned earlier are some of the popular indoor plants in the market. It is important that you do your due diligence and research on how you can prevent poisoning when considering them. If you have given enough thought on this matter but still want to purchase these plants then make sure that you take proper precautions.

  • Identify your indoor plants and know which ones are poisonous to your kids and pets.
  • Raise those plants off the floor. Place them in places where your kids cannot reach.
  • Label those plants that are toxic.
  • Always wear protective gear when maintaining your toxic plants.
  • Never rub your face, arms, and eyes when working with these plants.
  • Wash your hands after handling these types of plants.
  • Educate your kids about the dangers of the toxic plant.
  • Clean fallout often and discard clippings properly.
  • Put your poisonous plants in cages or baskets if you don’t want your cat reaching it.

First aid

If for some reason you had skin contact with a poisonous plant and is suffering from the symptoms, follow these steps as first aid for the affected area and then call an ambulance if needed or drive to the nearest hospital.

  1. If possible, identify the plant that caused the reaction.
  2. Determine if the plant poison needs proper medical attention or can be treated at home.
  3. Wash the affected area with soap and clean water. Your dishwashing soap or detergent can work on these cases and also rubbing alcohol.
  4. Brush the under nails of the person suffering from the symptoms to avoid further contact in other body parts.
  5. Apply a layer of hydrocortisone cream to relieve the itchiness or use some calamine lotion. If both are not readily available, use a wet compress. Oatmeal baths can help relieve itchiness too.
  6. If an antihistamine product is available, it can be taken or given to relieve the itching. Note that sleepiness can be a side effect of this drug.
  7. Seek professional help if symptoms worsen.

For accidental ingestion, follow the steps below:

  1. Remove or spit out the plant pieces from the mouth.
  2. Rinse mouth and lips with plenty of water.
  3. Sips of water should be given to prevent choking.
  4. Wash hands with plenty of soap and water.
  5. Call your poison center, hospital or ambulance if needed immediately.

Bonus: Most Poisonous Plants in the World

Beauty in plants can sometimes harbor deadly secrets; poison. Plants that produce deadly poison have the characteristics of being beautiful and produces vibrant flowers that attract the attention of humans.

It is no wonder why a few of the poisonous plants have become a staple in indoor and outdoor gardening. Be cautious when handling this plant if you already own some and stay away from them if you encounter them in the wild.

Ageratina altissima

White Snakeroot Ageratina altissima

This plant contains the toxin called tremetol which can cause vomiting, gastrointestinal problems, tremors and when left untreated death.

Oleander Nerium oleander

This has been widely used in gardens as a decorative plant but this beauty packs a powerful toxin within its whole body. Numerous types of cardiac glycosides are present in this plant and can cause heart failure due to cardiac arrest if ingested even in small amounts.

Hemlock Conium

A substance called coniine is the main toxin of this plant. The ingestion of the said substance can cause ascending paralysis which can lead to death once your lungs stop moving.


Angels Trumpet Brugmansia

This plant contains scopolamine and atropine which when ingested can be fatal to humans. The name seems to imply that once you ingest this plant, you’ll hear the angel’s trumpet welcome you to the afterlife.

Wolfsbane Aconitum

Ancient hunters have used this plant in preparation of their poison-tipped arrow. This plant contains aconitine neurotoxin and cardiotoxin that is very deadly to humans. Once ingested or introduced to the bloodstream, it can lead to intestinal failure, weakness, and heart or lung paralysis.

Rosary Pea Abrus precatorius

This is a native plant of Indonesia and is used to make drums that are used in rituals and gatherings. The seed of this plant contains abrin which disrupts bodily functions at a cellular level. It is said that one seed contains enough abrin to kill a person.

The Suicide Tree Cerbera odollam

This tree is a part of the Oleander family and is also very poisonous to humans. The seeds of this tree contain a substance called cerberin which when consumed in large amounts can cause irregular heartbeat and eventually death.

Castor Oil Plant Ricinus communis

Castor Oil Plant Ricinus communis

This is a plant that is found in houses and gardens all over the globe. It’s seeds hold the Guinness World Book Record for being the most poisonous plant. It contains a chemical that is called ricin that creates havoc in your whole body to the cellular level.

Ingestion of the castor oil plant seed produces a burning sensation inside the mouth and throat, followed by acute abdominal pain and bloody diarrhea that can lead to death if left untreated.

Manchineel Hippomane mancinella

Also known as “little apple of death”. Leave it alone when you encounter this plant in the wild. This tree can cause adverse skin reaction like rashes, blisters, and inflammation. This reaction is caused by a substance called phorbol that can also cause nausea, vomiting, diarrhea, and seizures if exposed in large quantities.

Dumb Cane Dieffenbachia

This is also a very popular indoor plant around the world. But the beautiful, shiny and wide leaves of this plant contain raphides that can cause excessive drooling, swelling of the lips mouth and tongue, and in severe cases speech disruption and difficulty in breathing due to airway blockage that can lead to death.


To summarize everything, it is best to be well informed when you are dealing with poisonous plants. Most of the indoors plants mentioned in this article are poisonous to some extent, but it is best to always remember that poisonous does not mean deadly. It means that it is harmful to one’s health when ingested, inhaled or absorbed by the body.

The friendliest looking plant can sometimes hide a very dangerous secret. It may look beautiful and lively but can also contain toxins that can make you sick.

Learn how to identify poisonous plants from the ones that are not and if you happen to already own some then make sure that you take precaution and put it in a place where your kids and pets can’t reach them.

It will help you and your family feel secure and safe. If you happen to own some of the plants mentioned here, it is also highly recommended to learn the first aid for plant poisoning.

Different methods are taken during skin contact and ingestion of these plants but ultimately it leads to medical attention if the symptoms worsen.