Brake Fluid: A Sweet Poison
The Bottom Line
Most brake fluids contain diethylene glycol (DEG). DEG has a sweet taste making it attractive to children and pets. DEG poisoning does not produce many initial symptoms, but it can cause substantial kidney damage if not treated promptly.
What is brake fluid?
The braking systems in most cars and many other machines rely on brake fluid. These hydraulic systems consist of a series of interconnected tubes, reservoirs, and pistons. Pushing down on the brake pedal increases the pressure on the brake fluid, which then causes the brake shoes to move and grab the brake disc, which slows or stops the car. Brake fluid products most often contain the toxic alcohol diethylene glycol (DEG), which is sweet-tasting, odorless, and colorless.Is brake fluid poisonous?
If swallowed, DEG can be very dangerous, and even fatal, if patients do not receive prompt medical care. Small children (and pets) will drink sweet-tasting brake fluid containing DEG. If the ingestion is recognized right away and the child receives emergency medical care, the likelihood of serious poisoning is greatly reduced.What are the symptoms of brake fluid poisoning?
DEG poisoning has 3 characteristic phases. The first phase consists of drunkenness, vomiting, and changes in the body’s acid balance (acidosis). In the second stage, the acidosis worsens and liver and kidney injury develop, which can lead to death if not treated. The final stage consists of delayed and sometimes fatal neurological effects, including changes in the brain and spinal cord, optic nerve damage, and complete or partial muscle paralysis. Early diagnosis and treatment are essential in preventing such complications. DEG toxicity can be minimized by fomepizole—a drug stocked in hospitals.Is diethylene glycol in products other than brake fluid safe?
DEG has been connected to at least 12 mass poisonings, not because of its use in brake fluid but because it was used in products intended for human consumption. The first documented mass poisoning was in 1937, when a drug manufacturer introduced an elixir of sulfanilamide (an antibiotic) made with DEG. At least 105 people died. The Federal Food, Drug, and Cosmetic Act of 1938 was passed following this tragedy to provide more consumer protection.
In 2008–2009, 57 children under 3 years of age were poisoned with DEG in Nigeria; 54 of them died from kidney failure. Almost all of the children had been given an acetaminophen-containing teething medication. DEG contamination was found in bottles of the medication from children’s homes and in 4 batches of the product from the manufacturer.
In Panama in 2006, at least 78 people died from unexplained kidney failure and nervous system illnesses. It was determined later that a cough syrup was contaminated with DEG. The syrup was manufactured using "glycerin" imported from China. That "glycerin" contained 22% DEG.
What to do if brake fluid gets in your eyes.
When brake fluid gets into the eyes, minor irritation and redness can occur. A serious eye injury is not likely, but the eyes should be rinsed immediately. Remove contact lenses and use lots of room-temperature water to flush the eyes. For children, pour water onto the forehead and let it gently run into the eyes. Encourage blinking. After rinsing, check the webPOISONCONTROL online tool for expert guidance, or call Poison Control at 1-800-222-1222.
What to do if you think someone drank brake fluid.
If someone swallows brake fluid, or if you have a question about using brake fluid 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.
Mary Elizabeth May, RN, BA, MPH
Certified Specialist in Poison Information
Professor of Pharmacy Emeritus
Poison Control Media Information
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Poisoned?
Call 1-800-222-1222 or
Prevention Tips
- Always store brake fluid away from children and pets; they might like the sweet taste.
- Store brake fluid in its original container in a cool and well-ventilated area.
- Dispose of used brake fluid according to the hazardous waste regulations of your community.
- Do not pour brake fluid down storm drains or on the ground since this can cause contamination of water or soil. Spills can also attract dogs and other animals.
This Really Happened
Case 1. Two adult brothers were brought to an ED 24 hours after swallowing 40–60 mL of brake fluid along with 80 mL of rum in an apparent suicide attempt. Both had severe vomiting and decreased urine output. Both required hemodialysis. One was dialyzed 6 times, and the other was dialyzed 8 times. Both men developed kidney failure but recovered well enough within a week to be discharged from the hospital.
Case 2. A 3-year-old girl drank brake fluid from a container that she found in the family car. Her parents took her to an ED. When she arrived, the girl was vomiting. The girl received fomepizole, the antidote for DEG and other toxic alcohols found in brake fluid, , until the blood concentrations of the alcohols were negative. After 2 days in the hospital, she was fine and was sent home.
For More Information
Sullivan R. Automotive products. American College of Medical Toxicology. Accessed May 1, 2024.References
Hoyte CO, Leikin JB. Management of diethylene glycol ingestion. Clin Toxicol (Phila). 2012;50(6):525-527.
Perazella MA. Hiding in plain sight: catastrophic diethylene glycol poisoning in children. Kidney360. 2023;4(11):1534-1535.
Reddy NJ, Sudini M, Lewis LD. Delayed neurological sequelae from ethylene glycol, diethylene glycol and methanol poisonings. Clin Toxicol (Phila). 2010;48(10):967-973.
Ross JA, Borek HA, Holstege CP. Toxic alcohols. Crit Care Clin. 2021;37(3):643-656
Schep LJ, Slaughter RJ, Temple WA, Beasley DM. Diethylene glycol poisoning. Clin Toxicol (Phila). 2009;47(6):525-535.
Schier JG, Rubin CS, Miller D, Barr D, McGeehin MA. Medication-associated diethylene glycol mass poisoning: a review and discussion on the origin of contamination. J Public Health Policy. 2009;30(2):127-143.
Sharma N, Jain S. Toxicity of brake oil. Emerg Med J. 2002;19(3):267-268.
Poisoned?
Call 1-800-222-1222 or
Prevention Tips
- Always store brake fluid away from children and pets; they might like the sweet taste.
- Store brake fluid in its original container in a cool and well-ventilated area.
- Dispose of used brake fluid according to the hazardous waste regulations of your community.
- Do not pour brake fluid down storm drains or on the ground since this can cause contamination of water or soil. Spills can also attract dogs and other animals.
This Really Happened
Case 1. Two adult brothers were brought to an ED 24 hours after swallowing 40–60 mL of brake fluid along with 80 mL of rum in an apparent suicide attempt. Both had severe vomiting and decreased urine output. Both required hemodialysis. One was dialyzed 6 times, and the other was dialyzed 8 times. Both men developed kidney failure but recovered well enough within a week to be discharged from the hospital.
Case 2. A 3-year-old girl drank brake fluid from a container that she found in the family car. Her parents took her to an ED. When she arrived, the girl was vomiting. The girl received fomepizole, the antidote for DEG and other toxic alcohols found in brake fluid, , until the blood concentrations of the alcohols were negative. After 2 days in the hospital, she was fine and was sent home.