Objective To explore the recovery rate of exhale CO 2 and energy expenditure in the patients with cirrhosis.Methods The recovery rate of exhale CO 2 and energy expenditure in fourteen patients with cirrhosis and eleven healthy subjects were measured by using NaH 13 CO 3 as tracer.After overnight fast,all subjects were intravenously given NaH 13 CO 3 at a primed constant rate of infusion for two hours after a saturating dose infusion.Amount of 13 CO 2 in exhale air was measured using stable isotope mass spectrometry analysis,and the recovery rate of exhale CO 2 and energy expenditure were calculated.Results The recovery rate of exhale CO 2 in patients with Cirrhosis was (80 7?0 26)%,and in healthy control subjects was (78 3?0 84)%,which showed a significantly different between the two groups(P0 05)[(30 2?2 4)Kcal?kg -1 ?d -1 and (28 4?3 5)Kcal?kg -1 ?d -1 ,respectively].Conclusions The results provide theoretical basic to calculate meals for nutritional therapy in the patients with cirrhosis.