9-Hydroxyoctadecadienoic acid (or 9-HODE) has been used in the literature to designate either or both of two stereoisomer metabolites of the essential fatty acid, linoleic acid: 9(S)-hydroxy-10(E),12(Z)-octadecadienoic acid (9(S)-HODE) and 9(R)-hydroxy-10(E),12(Z)-octadecadienoic acid (9(R)-HODE); these two metabolites differ in having their hydroxy residues in the S or R configurations, respectively. The accompanying figure gives the structure for 9(S)-HETE. Two other 9-hydroxy linoleic acid derivatives occur in nature, the 10E,12E isomers of 9(S)-HODE and 9(R)-HODE viz., 9(S)-hydroxy-10E,12E-octadecadienoic acid (9(S)-EE-HODE) and 9(R)-hydroxy-10E,12E-octadecadienoic acid (13(R)-EE-HODE); these two derivatives have their double bond at carbon 12 in the E or trans configuration as opposed