Butylated hydroxyanisole (BHA) is a synthetic antioxidant used as a food preservative to prevent oxidative rancidity in fats and oils.
It is chemically classified as a mixture of two isomeric organic compounds: 2-tert-butyl-4-hydroxyanisole and 3-tert-butyl-4-hydroxyanisole, with the molecular formula C11H16O2.
BHA is commonly added to products such as snack foods, chewing gum, butter, cereals, and baked goods. The U.S. Food and Drug Administration (FDA) classifies BHA as "Generally Recognized As Safe" (GRAS) when used in specified amounts (up to 0.02% of the fat or oil content in foods), but its use is restricted or prohibited in some other countries due to concerns over potential carcinogenicity.
See also the closely related preservative, BHT.