Plant Poisoning from Oxalates

Updated: Jul 25, 2023
  • Author: Jason F Kearney, MD, MBA; Chief Editor: Sage W Wiener, MD  more...
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Practice Essentials

Plant exposures are some of the most frequent poisonings reported to poison control centers. Exposures to plants containing oxalate crystals, such as Philodendron and Dieffenbachia, are among the most common toxic plant exposures reported in the United States.

Historically, the irritant properties of the Dieffenbachia plant have had various uses, including punishing slaves and treating gout, impotence, and frigidity. Currently, plants containing oxalate are admired for their ornamental beauty and found in public places and homes.

The following plants contain oxalates:

  • Anthurium ( Anthurium species) [1]
  • Arum, Araceae ( Arisaema species)
  • Caladium ( Caladium bicolor) (see the image below)
  • Calla lily ( Zantedeschia species)
  • Chinese evergreen ( Aglaonema species)
  • Dieffenbachia ( Dieffenbachia species) [2]  (see the image below)
  • Dieffenbachia, commonly known as dumb cane Dieffenbachia, commonly known as dumb cane
  • Jack-in-the pulpit ( Arisaema triphyllum) (see the image below)
    Jack-in-the-Pulpit Jack-in-the-Pulpit
  • Monstera, Ceriman ( Monstera deliciosa) (see the image below)
    Monstera deliciosa Monstera deliciosa
  • Nephthytis ( Syngonium podophyllum)
  • Philodendron ( Philodendron species) (see the image below)
    Philodendron Philodendron
  • Pothos or Hunter's robe ( Epipremnum aureum)
  • Skunk cabbage ( Symplocarpus foetidus) (see the images below)
  • Skunk Cabbage Skunk Cabbage
    Skunk Cabbage Skunk Cabbage


Nonsoluble calcium oxalate crystals are found in plant stems, roots, and leaves. The stalk of the Dieffenbachia plant produces the most severe reactions. These needlelike crystals produce pain and edema when they contact lips, tongue, oral mucosa, conjunctiva, or skin. [3] Edema primarily is due to direct trauma from the needlelike crystals and, to a lesser extent, by other plant toxins (eg, bradykinins, enzymes). [4, 5]



Philodendron and Dieffenbachia exposures are among the most common plant exposures reported to poison control centers. The 2021 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS), documented 5840 single exposures for oxalate plant poisonings. [6]

The majority of oxalate plant exposures occur in children younger than 5 years while sampling houseplants in the home. The 2021 NPDS report noted 4204 oxalate plant exposures in those younger than 6 years, 713 exposures in those aged 6-12 years, 179 in those 13-19 years old, and 561 exposures in those age 20 years and older. [6]



Most patients who have been exposed to plants containing oxalates completely recover. In most cases, nonsoluble oxalate plants produce self-limited symptoms and clinical manifestations. Significant morbidity or mortality is extremely rare.  However, there are case reports of severe oropharyngeal inflammation and edema, with impending obstruction of the upper airways. [7]   

The 2021 Annual Report of the American Association of Poison Control Centers' NPDS reported 1225 minor outcomes, 80 moderate outcomes, and 4 major outcomes, but no deaths from oxalate plant exposures. [6]