Metabolism of 14C-trans-sobrerol (I) by Sprague-Dawley rat liver microsomes did not result in covalent binding to proteins, lipid peroxidation or cytochrome P-450 destruction. 2. Subacute and chronic treatment of Sprague-Dawley rats with (I) resulted only in an increase in liver cytosolic GSH-S-transferase. 3. Acute treatment of rats with trans-sobrerol or its metabolite, 8-hydroxycarvotanacetone (II) produced considerable GSH depletion, faster in the case of II, in both liver and lung; the original GSH levels were restored within 24 h. No significant increase in lipid peroxidation was found even when GSH was at its lowest level. 4. UDP-glucuronyltransferase and GSH-S-transferase conjugation occurred with trans-sobrerol and some of its metabolites although at low rates.