The hydroxycineole (2) and cineolic acid (3) obtained as urinary metabolites from the brushtail possum (Trichosurus vulpecula) after the ingestion of l,8-cineole (1), are partial racemates. The compounds have been examined by gas chromatographic analysis over chiral stationary phases, and by the synthesis of optically pure enantiomers. Female possums show different enantiomeric ratios from males. Possible advantages to the animal in the use of a partial racemate as a pheromone are discussed.