In vitro metabolites of 1-phenylcyclohexene produced by the 10,000g supernatant fraction from rat liver homogenates were identified by a combination of spectrometric, chromatographic, and synthetic techniques. Initial oxidation occurred in the 3-position of 1-phenylcyclohexene to yield 1-phenyl-1-cyclohexen-3-one and 1-phenyl-1-cyclohexen-3-ol. Further allylic oxidation at the 6-position occurred to form 1-phenyl-6-hydroxy-1-cyclohexen-3-one and 1-phenyl-1-cyclohexene-3,6-diol. Trans-1-phenyl-1-cyclohexene-3,4-diol was also found and may have resulted from hydroxylation of 1-phenyl-1-cyclohexen-3-one alpha to the carbonyl to yield 4-hydroxy-1-phenyl-1-cyclohexen-3-one (not isolated) followed by carbonyl reduction. Oxidation of the double bond also occurred to give the cis and trans isomers of 1-phenylcyclohexane-1,2-diol as well as a compound postulated to be 1-phenylcyclohexane-1,2,3-triol.