The xanthines paraxanthine, xanthine, and uric acid are absorbed completely by the turtlePseudemys scripta elegansand metabolised presumably into CO2and NH3. No intermediate metabolites are excreted. Caffeine, hydroxycaffeine, theobromine, hydroxytheobromine, and hydroxyparaxanthine are absorbed and excreted in different amounts or percentages of the dose administered. Intermediate metabolites of these compounds are not excreted. The turtlePseudemys scripta elegansmay, therefore, be ammonotelic.