Rent Shop Volunteer Join

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
1 rating

Saturday - August 24, 2013

From: Richmond, TX
Region: Southwest
Topic: Non-Natives, Poisonous Plants
Title: Does non-native Crown of Thorns cause cancer?
Answered by: Nan Hampton

QUESTION:

Does the plant, Corona De Cristo (Crown of thorns) cause cancer?

ANSWER:

First of all, the focus and expertise of the Lady Bird Johnson Wildflower Center is with plants native to North America.  Euphorbia milii (Crown of Thorns) is native to Madagascar and, thus, is really out of our purview.  However, I can point you to several internet sources where you can find out more about it.

Poisonous Plants of North Carolina lists it as being mildly toxic and, according to the University of Florida Miami-Dade Cooperative Extension Service:

"As with other euphorbs, E. milii produces copious quantities of poisonous milky sap that can cause skin irritation, and contains tumor promoting chemicals (diterpene esters).  It would be best to wear gloves when handling the plants, and to wash off any sap that gets on your skin."

Here is more information from Union County College in New Jersey.

There are rumors about the plant having cancer causing abilities and several of the sites listed above note that the sap has chemicals that are known tumor promoters.  However, a study testing the sap on mice skin did not produce tumors.  [Delgado, I. F. et al.  2003. Absence of tumor promoting activity of Euphorbia milii latex on the mouse back skin.  Toxicol. Lett. 2003 Nov 30;145(2):175-80.]

If I were you, I would use caution in handling the plant and, as the advice from Miami-Dade Cooperative Extension Service recommends—wear gloves and wash off any sap that gets on your skin.

 

More Poisonous Plants Questions

Plant for privacy hedge in Oklahoma that is not poisonous to dogs
April 01, 2012 - Hello! I am looking to put a privacy hedge fence in my yard. I love the look of American Holly, however, I have a dog who eats everything so I worry that this will not be a wise choice with the b...
view the full question and answer

Can a dog die from eating a holly bush?
January 12, 2016 - Can a dog die from eating a holly bush?
view the full question and answer

Poisonous weeds in Bedford County, PA
June 21, 2010 - I am battling my second bad round of poison in a month, this time on my face and in my left eye. It's awful. Problem is, I have looked and looked for poison ivy, oak and sumac around my neighborhoo...
view the full question and answer

Horse-friendly plants for Powell OH
September 24, 2010 - I am looking for horse friendly plants, i.e., shrubs, trees, bushes, etc. that can be planted in wet area in Ohio. Thank you in advance for your assistance.
view the full question and answer

Propagation of Mountain Laurel by seed
April 20, 2006 - I have a Texas Mountain Laurel. I found on this website that the beans are poisonous, but if you plant them, will they grow another Mountain Laurel?
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.