Uroterpenol (p-menth-1-ene-8,9-diol) is shown to occur in human urine as a β-D-glucuronide which has been isolated and characterised. The parent diol has been synthesised by oxidation of (+)-limonene with plumbic acetate and converted into a β-D-glucuronide identical with the natural product except that both materials are shown to be mixtures, in different proportions, of diastereoisomers configurationally identical at position 4 but differing at position 8. Periodates cleave the olefinic bond in uroterpenol with unexpected ease.