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Oxalic acid poisoning

Oxalic acid is a poisonous, colorless substance. This article discusses poisoning from swallowing oxalic acid.

This is for information only and not for use in the treatment or management of an actual poison exposure. If you have an exposure, you should call your local emergency number (such as 911) or a local poison control center at 1-800-222-1222.

Poisonous Ingredient

Oxalic acid

Where Found

Oxalic acid may be found in some:

Note: This list may not be all inclusive.


Symptoms of oxalic acid poisoning include:

Home Care

Seek immediate medical help. DO NOT make a person throw up unless told to do so by Poison Control or a health care professional.

If the chemical was swallowed, immediately give the person water or milk, unless instructed otherwise by a health care provider. DO NOT give water or milk if the person is having symptoms (such as vomiting, convulsions, or a decreased level of alertness) that make it hard to swallow.

Before Calling Emergency

The following information is helpful for emergency assistance:

  • Person's age, weight, and condition
  • Name of the product (ingredients and strengths, if known)
  • Time it was swallowed
  • Amount swallowed

However, DO NOT delay calling for help if this information is not immediately available.

Poison Control

In the United States, call 1-800-222-1222 to speak with a local poison control center. This hotline number will let you talk to experts in poisoning. They will give you further instructions.

This is a free and confidential service. 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.

What to Expect at the Emergency Room

The health care provider will measure and monitor vital signs, including temperature, pulse, breathing rate, and blood pressure. The person may receive:

  • Activated charcoal
  • Airway support, including oxygen, breathing tube through the mouth (intubation), and breathing machine (ventilator)
  • Blood and urine tests
  • Camera down the throat (endoscopy) to see burns in the food pipe (esophagus) and stomach
  • Chest x-ray
  • EKG (electrocardiogram, or heart tracing)
  • Fluids through a vein (intravenous or IV)
  • Medicines to treat symptoms
  • Tube through the mouth into the stomach to wash out the stomach (gastric lavage)

Outlook (Prognosis)

How well a person does depends on the amount of poison swallowed, how concentrated the poison is, and how quickly treatment was received. The faster a person gets medical help, the better the chance for recovery.

Severe damage to the mouth, gastrointestinal tract, or airway may occur and quickly cause death if not treated.


Caustics. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 153.

Update Date 1/13/2015