Antifreeze contains chemicals that are toxic if a person ingests them. Antifreeze poisoning can be life-threatening and requires immediate medical attention.

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People add antifreeze to vehicle radiators to prevent the liquid coolant inside from freezing and overheating. Antifreeze typically contains ethylene glycol, methanol, and propylene glycol.

Although the chemicals in antifreeze are relatively nontoxic, the body can metabolize them into highly toxic alcohol byproducts.

Symptoms of antifreeze poisoning may take time to develop, and they can be similar to alcohol intoxication

Anyone who suspects that they or someone else has ingested antifreeze should seek immediate medical attention or call the American Association of Poison Control Centers (AAPCC) for expert advice at 1-800-222-1222. The AAPCC helpline is open 24 hours and is toll-free.

In this article, we discuss what to do if someone ingests antifreeze. We also cover symptoms, treatment, and complications of antifreeze poisoning.

We also discuss what antifreeze is and tips for preventing accidental ingestion.

What to do

Share on PinterestIt is imperative that a person seeks immediate medical attention if they have ingested antifreeze.
A person should call 911 immediately or go straight to the emergency room if they suspect that they or someone else has ingested antifreeze.

It is vital to seek help, even if a person does not show or feel symptoms of antifreeze poisoning.

People who are unsure whether they or someone else has ingested antifreeze can also call the AAPCC for expert advice at 1-800-222-1222. The AAPCC helpline is open 24 hours and is a toll-free number.

Accidentally ingesting antifreeze can happen for many reasons. For example, children may drink antifreeze because ethylene glycol tastes sweet. However, manufacturers often add substances that make antifreeze taste bitter to reduce a person’s desire to drink it.

A person may accidentally drink antifreeze that someone has stored in an unlabeled container, such as a glass, food jar, or drinks bottle.

However, ingesting antifreeze is not always accidental. Some individuals may use antifreeze as an alternative source of alcohol.

Other people may intentionally ingest antifreeze as a means of self-harm or in an attempt to take their own life.


Symptoms of antifreeze poisoning may not appear immediately after a person ingests it, as it takes time for the body to metabolize the chemicals.

The body converts the chemicals in antifreeze into smaller alcohols and acids. These can include:

glycolaldehydeglycolic acidglyoxylateoxalic acid

The onset and severity of symptoms can vary according to several factors, such as the type and amount of antifreeze the person ingested.

In general, antifreeze poisoning occurs in three stages. We discuss each of these below:

First stage

The first stage of antifreeze poisoning typically begins between 30 minutes and 12 hours after a person ingests it.

The ethylene glycol in antifreeze affects the central nervous system first. Early symptoms of antifreeze poisoning may appear similar to those of alcohol intoxication.

These symptoms can include:

loss of coordinationslurred or jumbled speechdizzinesseuphorianausea and vomitingseizures

Second stage

People generally enter the second stage of antifreeze poisoning 12–24 hours after ingestion.

During this stage, the body continues to metabolize the chemicals in antifreeze into toxic acids. These acids lower the pH level of the blood, which leads to a condition called metabolic acidosis.

At this point, antifreeze poisoning will start to affect multiple organs, including the kidneys, brain, lungs, and liver.

People in the second stage of antifreeze poisoning may experience:

an irregular heartbeatshallow breathingfatigueconfusion

A person may also lose consciousness or go into a coma at this stage. A doctor may suggest more aggressive treatments for a person in the second stage of antifreeze poisoning.

Third stage

The third stage of antifreeze poisoning occurs 24–72 hours after ingesting it.

If a person does not receive treatment, a buildup of calcium oxalate crystals can lead to kidney failure.

Early diagnosis and treatment for antifreeze poisoning is essential to reduce a person’s risk of experiencing permanent organ damage and long-term health complications.

Treatment for antifreeze poisoning depends on:

the type and quantity of antifreeze a person has ingestedthe amount of time that has passed since ingestionthe type and severity of a person’s symptoms

Doctors focus treatment for antifreeze poisoning on:

preventing the body from continuing to metabolize the antifreezeremoving antifreeze and toxic metabolites from the person’s bloodstreamproviding supportive therapies, particularly in more severe cases that involve organ failure

Doctors prescribe antidotes, such as fomepizole and ethanol, to prevent a person’s body from metabolizing the chemicals in antifreeze into toxic metabolites.

Antidote therapy can help prevent further kidney damage but does not remove metabolites that have already collected inside the kidneys.

A doctor may then focus on returning the person’s blood pH to normal levels, such as by administering a bicarbonate solution through an intravenous line.

To remove unmetabolized antifreeze and toxic metabolites from the bloodstream, a doctor may also recommend hemodialysis.

During hemodialysis, a healthcare professional inserts a tube with a needle into a person’s arm. The tube connects to a dialysis machine.

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The person’s blood flows along the tube into the machine, which filters out toxins and waste products. The filtered blood then passes through another tube back into the person’s arm.