ChEBI: Vanillylmandelic acid is an aromatic ether that is the 3-O-methyl ether of 3,4-dihydroxymandelic acid. It has a role as a human metabolite. It is an aromatic ether, a 2-hydroxy monocarboxylic acid and a member of phenols. It is functionally related to a mandelic acid. It is a conjugate acid of a vanillylmandelate.