The effects of trans-resveratrol (RSV) combined with ethanol (EtOH) were evaluated by 31P NMR on total ATP and sn-glycerol-3-phosphate (sn-G3P) contents measured in real time in isolated and perfused whole liver of the rat. Mitochondrial ATP turnover was assessed by using specific inhibitors of glycolytic and mitochondrial ATP supply (iodacetate and KCN, respectively). In RSV alone, the slight decrease in ATP content (−14 ± 5% of the initial content), sn-G3P content and ATP turnover were similar to those in the Krebs-Henseleit buffer control. Compared to control, EtOH alone (14 or 70 mmol/L) induced a decrease in ATP content (−24.95 ± 2.95% of initial content, p < 0.05) and an increase in sn-G3P (+158 ± 22%), whereas ATP turnover tended to be increased. RSV (20 μmol/L) combined with EtOH, (i) maintained ATP content near 100%, (ii) induced a 1.6-fold increase in mitochondrial ATP turnover (p = 0.049 and p = 0.004 vs EtOH 14 and 70 mmol/L alone, respectively) and (iii) led to an increase in sn-G3P (+49 ± 9% and +81 ± 6% for 14 and 70 mmol/L EtOH, respectively). These improvements were obtained only when glycolysis was efficient at the time of addition of EtOH + RSV. Glycolysis inhibition by iodacetate (IAA) evidenced an almost 21% contribution of this pathway to ATP content. RSV alone or RSV + EtOH prevented the ATP decrease induced by IAA addition (p < 0.05 vs control). This is the first demonstration of the combined effects of RSV and EtOH on liver energy metabolism. RSV increased (i) the flux of substrates through ATP producing pathways (glycolysis and phosphorylative oxidation) probably via the activation of AMPkinase, and (ii) maintained the glycolysis deviation to sn-G3P linked to NADH + H+ re-oxidation occurring during EtOH detoxication, thus reducing the energy cost due to the latter.