What is automotive antifreeze?
Antifreeze is added to water in automotive radiators to simultaneously raise the boiling point and lower the freezing point of radiator fluid. This reduces the chances of boil-overs and ice forming in the cooling system. Most automotive antifreeze products contain high concentrations of ethylene glycol (EG) as the active ingredient. EG is odorless and colorless, but it has a sweet taste. The bright yellow-green color of many antifreeze products is from sodium fluorescein—a dye added to help identify system leaks.
What happens if you drink antifreeze? Is antifreeze poisonous?
Poisonings by antifreeze can be tricky to identify early on. For several hours after someone swallows it, everything seems fine. Meanwhile however, the body is busy breaking down the EG into a number of by-products that affect the blood chemistry, nervous system, and kidneys.
After a few hours, someone poisoned by antifreeze can seem drunk or groggy and complain of stomach distress. After a few more hours, the victim might go into a coma. The kidneys can be damaged and stop making urine. If the victim survives, there could be permanent damage to the kidneys and brain. EG toxicity can be minimized by fomepizole—a drug stocked in hospitals.
If antifreeze is dangerous to swallow, why does it taste so good?
The natural taste of EG is sweet. This makes it attractive to children and pets, although some adults can be fooled by the sweet taste. Many antifreeze brands contain an added bitter substance to discouraging someone from drinking more than a sip. While this sounds like a good idea, studies so far don't prove it to be effective.
Can antifreeze hurt your skin?
Spilling antifreeze onto the skin happens frequently. If it is washed off promptly, nothing more than mild irritation is likely to occur.
Are there safer products you can use besides ethylene glycol antifreeze?
Some brands of antifreeze contain propylene glycol, which is less dangerous if swallowed than EG. If you decide to use this type of antifreeze, check your car’s owners' manual to be sure you will not void your warranty. Also check with your mechanic. You would need to flush and drain your cooling system first.
How to safely dispose of antifreeze.
Antifreeze is a hazardous material that can contaminate soil and water. Fortunately, it can be recycled. How to dispose of used antifreeze depends on where you live. Some communities accept antifreeze at household hazardous waste collection stations; contact your local environmental services department or department of public works to learn about your options. Also, in some states, designated service stations are authorized to collect used antifreeze for recycling.
What to do if you think someone drank antifreeze.
If someone swallows antifreeze, gets antifreeze in the eyes, or if you have a question about using antifreeze safely, help from experts is available through the webPOISONCONTROL online tool and by phone at 1-800-222-1222. Poison Control’s expert guidance is always free, confidential, and available 24 hours a day.
Rose Ann Gould Soloway, RN, BSN, MSEd, DABAT emerita
Clinical Toxicologist
Revised William G. Troutman, PharmD
Professor of Pharmacy Emeritus
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Prevention Tips
- Store antifreeze in its original container, locked where children can't see or reach it.
- Don't use antifreeze when children or pets are around.
- Re-close the cap tightly after use.
- Never transfer antifreeze to another container, especially a food or drink container.
- Clean up any spills or leaks immediately. Dispose of used antifreeze according to the hazardous waste regulations of your community.
- Do not pour antifreeze down storm drains or onto the ground since this can cause contamination of water or soil. Spills can attract dogs and other animals.
This Really Happened
Case 1. The parent of a 3-year-old girl put antifreeze in a water bottle. The product contained ethylene glycol (EG). The child then drank from the bottle, but her parents didn't know how much she swallowed. They called Poison Control who advised them to take her to the nearest emergency room right away. Poison Control provided the emergency physician with treatment advice: obtain an EG blood concentration and treat the child with fomepizole (a drug that blocks the production of toxic EG by-products). The child was in the hospital for 24 hours of treatment.
Case 2. A 67-year-old man swallowed an unknown amount of antifreeze and was taken to the ED. He became very lethargic, confused, and had difficulty speaking. He was intubated and placed on a ventilator. His lab work showed a high ethylene glycol level and his electrolytes were abnormal so the treatment team administered fomepizole and dialysis was started. Even though he had 4 doses of fomepizole and 2 dialysis sessions, his kidneys had been damaged. He was released from the hospital after 5 days of treatment.