Are you sure either you or the doctor didn't confuse
ethylene glycol for propylene glycol?
"Ethylene glycol (once used as a component of antifreeze)
Ethylene glycol solutions became available in 1926 and were marketed as "permanent antifreeze" since the higher boiling points provided advantages for summertime use as well as during cold weather. They are used today for a variety of applications, including
automobiles, but
there are lower-toxicity alternatives made with propylene glycol available.
Poisoning
Main article:
Ethylene glycol poisoning
Ethylene glycol is poisonous to humans and other animals, and should be handled carefully and disposed of properly. Its sweet taste can lead to accidental ingestion or allow its deliberate use as a murder weapon. Ethylene glycol is difficult to detect in the body, and causes symptoms—including intoxication, severe ........, and vomiting—that can be confused with other illnesses or diseases. Its metabolism produces
calcium oxalate, which crystallizes in the brain, heart, lungs, and kidneys, damaging them; depending on the level of exposure, accumulation of the poison in the body can last weeks or months before causing death, but death by
acute kidney failure can result within 72 hours if the individual does not receive appropriate medical treatment for the poisoning. Some ethylene glycol antifreeze mixtures contain an
embittering agent, such as
denatonium, to discourage accidental or deliberate consumption.
Propylene glycol[component now used in antifreeze]
Propylene glycol is considerably less toxic than ethylene glycol and may be labeled as "non-toxic antifreeze". It is used as antifreeze where ethylene glycol would be inappropriate, such as in food-processing systems or in water pipes in homes where incidental ingestion may be possible. For example, the
FDA allows
propylene glycol to be added to a large number of
processed foods, including
ice cream,
frozen custard, salad dressings, and
baked goods, and
it is commonly used as the main ingredient in the "e-liquid" used in electronic cigarettes."
Early anti-vaping propaganda references to e-cigarettes having antifreeze chemicals is only partially true. Yes, e-liquid has the modern non-toxic chemical propylene glycol, but not the older toxic chemical ethylene glycol. It's all about chemistry, baby.

You can now tell your know-it-all doctor friend he needs to brush up on his chemistry.