Objective To investigate the effects of enflurane (Enf)at normothermia or hypothermia on myocardial energy metabolism. Methods Twenty-four isolated rabbit hearts, perfused with modified Krebs-Hensleit buffer using Langendorff's device in 15 min, were randomly assigned to be perfused with 1. 1 % Enf at normothermia (37℃ ), 2. 2 % Enf at normothermia (37℃ ), 1. 1 % Enf at hypothermia (30℃ ), or 2. 2 % Enf at hypothermia (30 ℃ ), respectively. The myocardial adenine nucleotides contents, activities of ATPases were measured after 30min perfusion. Results In group 2.2% Enf, ATP content was significantly higher and the activity of Na+ -K+ ATPase was significantly lower than those in group 1. 1 % Enf at normothermia or hypothermia (P