A monocarboxylic acid that is (E)-penta-2,4-dienoic acid substituted by a 1,3-benzodioxol-5-yl group at position 5. It has been isolated from black pepper (Piper nigrum). ChEBI: (E,E)-piperic acid is a monocarboxylic acid that is (E)-penta-2,4-dienoic acid substituted by a 1,3-benzodioxol-5-yl group at position 5. It has been isolated from black pepper (Piper nigrum). It has a role as a plant metabolite. It is a member of benzodioxoles and an alpha,beta-unsaturated monocarboxylic acid. It is functionally related to an (E)-penta-2,4-dienoic acid. It is a conjugate acid of an (E,E)-piperate.