(5Z,11Z,14Z,17Z)-8,9-epoxyicosatetraenoic acid is an EpETE obtained by formal epoxidation of the 8,9-double bond of all-cis-5,8,11,14,17-icosapentaenoic acid. It is functionally related to an all-cis-5,8,11,14,17-icosapentaenoic acid. It is a conjugate acid of a (5Z,11Z,14Z,17Z)-8,9-epoxyicosatetraenoate.