As an antifreeze poisoning treatment, ethanol prevents the key ingredient in antifreeze, the ethylene glycol, from being metabolized into toxic chemicals in the body. This lets the body remove the ethylene glycol harmlessly through the body’s waste. Simply speaking, the ethanol lets you “pee it out”.
Ethylene glycol is the major ingredient of almost all radiator fluid products in the United States. It is used to increase the boiling point and decrease the freezing point of radiator fluid, which circulates through the automotive radiator. These changes to the boiling and freezing points result from the colligative properties of the solute (ie, they depend on the number of particles in the solution). Hence, ethylene glycol is added to prevent the radiator from overheating or freezing, depending on the season. Fluorescein dye is often added to radiator fluid to help mechanics identify the source of a radiator leak. The fluorescein in the fluid fluoresces when viewed under ultraviolet light.
Ethylene glycol tastes sweet, which is why some animals are attracted to it. Many veterinarians are familiar with ethylene glycol toxicity because of the frequent cases that involve dogs or cats that drink radiator fluid.