The harmful substances in elephant ear plants are:

• Oxalic acid
• Asparagine, an amino acid found in this plant

Note: Leaves and stems are the most dangerous when eaten in large amounts.

Elephant ear grows naturally in tropical and subtropical areas. It is also common in northern climates.

Symptoms of elephant ear poisoning are:

• Blisters in the mouth
• Burning in mouth and throat
• Increased saliva production
• Pain when swallowing
• Hoarse voice
• Diarrhea
• Nausea and vomiting
• Redness, pain, and burning of the eyes
• Swelling of the tongue, mouth, and eyes

Blistering and swelling in the mouth may be severe enough to prevent normal speaking and swallowing.

Wipe out the mouth with a cold, wet cloth. Wash off any plant sap on the skin. Rinse out the eyes.

Do not make the person throw up unless poison control or a health care provider tells you to.

Have this information ready:

• Person's age, weight, and condition
• Part of plant swallowed, if known
• Time swallowed
• Amount swallowed

Your local poison control center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States. This national hotline will let you talk to experts in poisoning. They will give you further instructions.

This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.

Take the plant with you to the hospital, if possible.

The provider will measure and monitor the person's vital signs, including temperature, pulse, breathing rate, and blood pressure. Symptoms will be treated as appropriate. The person may receive fluids through a vein (IV) and breathing support. Corneal damage will require additional treatment, possibly from an eye specialist.

If contact with the person's mouth is not severe, symptoms usually resolve within a few days. For people who do have severe contact with the plant, a longer recovery time may be necessary.

In rare cases, oxalic acid causes swelling severe enough to block the airways.

Do not touch or eat any plant that you are not familiar with. Wash your hands thoroughly after working in the garden or walking in the woods.

Graeme KA. Toxic plant ingestions. In: Auerbach PS, Cushing TA, Harris NS, eds. Auerbach's Wilderness Medicine. 7th ed. Philadelphia, PA: Elsevier; 2017:chap 65.

Ryan ET, Hill DR, Solomon T, Aronson NE, Endy TP. Poisonous plants and aquatic animals. In: Ryan ET, Hill DR, Solomon T, Aronson NE, Endy TP, eds. Hunter's Tropical Medicine and Infectious Disease. 10th ed. Philadelphia, PA: Elsevier; 2020:chap 139.

Updated by: Jesse Borke, MD, CPE, FAAEM, FACEP, Attending Physician at Kaiser Permanente, Orange County, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.