Are tradescantias toxic?

Skip to: The problem with toxic plant lists // Why do people day tradescantias are toxic? // Are tradescantias safe for humans? // Are tradescantias safe for pets? // Conclusions

Houseplant owners are often concerned about safety and toxicity of plants – especially if there are also children or pets in the house. There are lots of online resources which claim to give information about the dangers of houseplants. But lots of those resources are unreliable, unsourced, and inaccurate.

Tradescantias, and Commelinaceae plants in general, are often included on “toxic” plant lists. Are they really dangerous?

In the rest of this article, I’ll explain where this information comes from, and why there are so many inaccurate claims out there.

The problem with toxic plant lists

Often, clickbaiting lists and AI-generated posts online will simply say a particular plant is “dangerous” or “unsafe” or “toxic”. But what does that actually mean? Without clarifying information, it’s impossible for any reader to make rational decisions about risk for themselves, their families or pets. These resources just end up scaring people into sharing unreliable and unhelpful information.

Different species are sucesptible to different toxins, so something that’s safe for a human might be harmful to a dog (and vice versa). Calling something “pet safe” is no clearer, because pets can range from mammals to birds and reptiles, which all have different needs. And even the most common species, cats and dogs, have different vulnerability to plant toxins.

Even narrowing down the risks to a particular animal species (like humans), there are still many different hazards a plant can have. The danger could be anything from physical injury, to stomach upset, to cardiac arrest. And those things could by caused by anything from touching the surface of the plant, to chewing the sap inside the stem, to eating large amounts of it every day over a long period.

It’s really not useful to group all of those possibilities together under the same simple “toxic” umbrella. But that’s what many popular resources do. Which makes it impossible for readers to make informed decisions about what risks they consider personally acceptable, and what they will do to mitigate them.

Why do people say tradescantias are toxic?

Most plants of the Commelinaceae family contain crystals of calcium oxalate in their cells. ^[1] Calcium oxalate is found naturally in many plants – including some which we use as food, like tea, spinach, and beets. In moderate quantities, it’s harmless and digestible, for humans and other animals. ^[2]

In sufficient quantities, the crystals can cause physical irritation to the skin of humans and animals, resulting in pain, swelling, and itching. Delicate skin like the inside of the mouth is more susceptible to this irritation. The effect is temporary and doesn’t cause long-term damage. ^[3]

Eating a very large quantity of calcium oxalate can lead to kidney damage, serious illness, and death in animals. The only species at real risk of this are herbivores which eat huge amounts of plants. Even then, calcium oxalate poisoning in livestock generally only happens if their diet is suddenly changed, or is limited to just one type of plant for a long time. ^[4] It would be almost impossible for a human, dog, or cat to eat enough of a calcium oxalate-containing plant to make them ill.

There hasn’t been any research into the exact levels of calcium oxalate in Commelinaceae plants. We know it’s present, but we don’t know whether it’s a lot compared to other plants.

This is why tradescantias end up on “toxic plant” lists. They contain a substance which has the potential to cause physical irritation, illness, and death in certain circumstances. But this one fact about a particular chemical found in the plant isn’t the only source of information about its safety. Let’s look at the other evidence.

Are tradescantias safe for humans?

Commelinaceae plants have been widely associated with humans around the world for a very long time. This means there have been a lot of opportunities for people to become aware of any dangers the plants might cause. Here’s the evidence we do have:

• There have been no documented cases of death or serious illness from tradescantia poisoning in humans. ^{[5] [6]}
• Several cultures have a long history of using various Commelinaceae plants medicinally. ^{[6] [7] [8]}
• Many species have also been used for food and drink by humans for a long time. ^{[9] [10] [11] [12]}
• There have been occasional reports of irritation to the mouth and skin. This is what we would expect for plants with moderate calcium oxalate levels. ^[13]
• There have been a few reports of specific allergies. ^[14] Allergic reactions happen when the immune system overreacts to something that’s not actually harmful. Any plant (and in fact, almost any substance) can cause an allergic reaction in susceptible people, and this isn’t evidence of any inherent danger in the plant itself.

Are tradescantias safe for pets?

Commelinaceae plants have been widely grown around the world for a long time, and people have been keeping animals in their homes for just as long. So again, there has been a lot of opportunity for risks to become apparent. Here’s the evidence available:

• There have been no documented cases of death or serious illness from tradescantia poisoning in dogs, cats, birds, reptiles, rabbits, rodents, or livestock. ^{[15] [16] [17] [18] [4]}
• In laboratory studies with mice and rats, researchers weren’t able to find a fatal dose of Commelinaceae plants even when they tried. ^{[19] [20] [21] [22]}
• Several Commelinaceae species are fed to livestock in some parts of the world. ^[12] All of this suggests that the calcium oxalate levels in Commelinaceae are not high enough to cause poisoning to animals, even when eaten in large quantities.
• As with humans, there are a few reports of pets with specific allergic reactions. ^[23] This can happen with any plant and doesn’t mean they are inherently toxic.
• It’s also fairly common for cats and dogs to vomit after eating any plant, because their digestive systems are not adapted to handle that diet. This again doesn’t mean that plants are toxic to cats and dogs, just that they aren’t naturally herbivores. ^{[24] [25]}

Conclusions

Tradescantias are not seriously dangerous plants. The only hazard they pose which isn’t universal to all plants is that their sap might sometimes cause short-term irritation to the skin, including the mouth if chewed or eaten.

Like all plants, eating a large amount can cause short-lived stomach upset in cats and dogs. And like almost anything, sensitive individuals can occasionally have allergic reactions.

There has never been a documented case of a human, pet, or livestock animal dying or becoming seriously ill as a result of eating Commelinaceae plants.

References

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11. Facciola, S. (1990). Cornucopia: a source book of edible plants. Kampong Publications. Internet Archive link.[↩]
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13. Morton, J.F. (1982). Plants poisonous to people in Florida and other warm areas. Southeastern Printing.[↩]
14. Wüthrich, B., Johansson, S. G. O. (2007). Allergy to the ornamental indoor green plant Tradescantia ‘Albifloxia’. Allergy, 52(5), 556-559. doi:10.1111/j.1398-9995.1997.tb02599.x[↩]
15. Siroka, Z. (2023). Toxicity of house plants to pet animals. Toxins, 15(5), 346. Open access link.[↩]
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19. Baghalpour, N., Ayatollahi, S. A., Naderi, N., Hosseinabadi, T., Taheri, Y., Mahroo-Bakhtiyari, J., Shinwari, Z. K., Khalil, A. T., & Sharifi-Rad, J. (2021). Antinociceptive and anti-inflammatory studies on Tradescantia zebrina. Pakistan Journal of Botany, 53(1), 357-365. Open access link.[↩]
20. Tiwari, S. K., Lahkar, M., Dash, S., Samudrala, P. K., Thomas, J. M., & Augustine, B. B. (2013). Preliminary phytochemical, toxicity, and anti-inflammatory evaluation of Commelina benghalensis. International Journal of Green Pharmacy, 7(3), 201-205. Open access link.[↩]
21. Njideka, A., Amarachi, I. S., Peter, I., Akachukwu, O., & Sylvester, N. C. (2021). Antiulcer activities of the methanol leaf extract and fractions of Commelina ascendens (Commelinaceae) using invitro and invivo models. Pharmacology Online, 2021(1), 336-348. Open access link.[↩]
22. Imtiaz, F., Islam, M., Saeed, H., Ahmed, A., & Rathore, H. A. (2023). Assessment of the antidiabetic potential of extract and novel phytoniosomes formulation of Tradescantia pallida leaves in the alloxan-induced diabetic mouse model. The FASEB Journal, 37(4). Open access link.[↩]
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