Two harmful chemicals — HHE and ethyl furan — show up together when you heat oils like perilla oil, and they both come from the same type of fat: linolenic acid.

When perilla oil is heated, two chemicals—HHE and ethyl furan—are made together because they both come from the same fat molecule, linolenic acid.

When you heat different cooking oils really hot for a long time, they break down and make harmful chemicals, and the type of oil you use determines which chemicals are made.

When you heat perilla oil (a type of plant oil) at high temperatures for a long time, it creates two specific chemicals—HHE and ethyl furan—that don’t show up when you heat other oils, because perilla oil has a special fat called linolenic acid.