May 6, 2002: What is the toxicity of common spring and summer plants?

Once again, Kim Barker, managing director of the hotlines, will address plants.  Next week will conclude our summer plant series with a question about pokeweed.


The MTPC receives the greatest number of calls about the following potentially toxic plants.  Most pediatric ingestions cause no symptoms or mild symptoms.


Azalea:  All plants in the rhododendron species may cause toxicity due to a grayanotoxin found in the plants. This is the same toxin found in contaminated honey.  Major clinical effects include burning of the mouth, perioral numbness and tingling, nausea, vomiting, diaphoresis, hypotension, bradycardia, coma, altered sensorium, and seizures.  More than three leaves or flowers are potentially toxic.


Honeysuckle:   Various species of honeysuckle are common in the South.  The rhododendron family causes toxicity similar to the azalea.  Other species are considered non-toxic. 


Daffodils: The toxin resides in the bulb and is found in lesser concentration in the stem and flower.  The daffodil is a member of the Amaryllidaceae plant family which contains alkaloids such as crinine, narcissine, and lycorine. The main toxic effect is GI irritation with severe vomiting, diarrhea, and abdominal pain.  The bulb also contains oxalate crystals which produce pain and a burning sensation in the mouth.


Irises:  The primary toxicity of a bulb is in the actual bulb.  Ingestion of the bloom is less toxic.  Symptoms include GI irritation, mouth and throat burning, vomiting and diarrhea. 


Assessment of any patient with plant ingestion should include assessment of the potential toxicity of the plant species.


Next week:  Pokeweed


I am interested in any questions that you would like answered in “Question of the Week.”  Please e-mail me with any suggestions at


Donna Seger, M.D.

Medical Director

Middle Tennessee Poison Center