Banana oil is the common name of the chemical compound properly known as amyl acetate, or C7H14O2. It is a colorless liquid ester derived from amyl alcohol, and although its scent strongly resembles that of bananas (hence the name), it is not found naturally in the fruit of the banana tree.
It’s used in various products, from perfume (for its odor) to chewing gum (for its flavor) to nail polish remover (for its solvent capability). Banana oil is also used in the preparation of penicillin, and is even a popular substance to test the fit of respirators, since its strong but pleasant odor will instantly be sensed if a leak is present in the seal.