BACKGROUND: It is well known that administration of nutrients, especially protein and amino acids mixtures, stimulates energy expenditure in the unanesthetized patients. Also, there were reports that the mechanisms for nutrient-induced thermogenesis are not impaired during general anaesthesia. The enhanced amino acid-induced thermogenesis would counteract the anaesthesia-induced reduction in metabolism and prevent the development of hypothermia. The present study was designed to see if completing the amino acid infusion before induction of anaesthesia would induce heat production, which would promote energy expenditure and thereby counteract the development of anaesthesia-induced hypothermia. METHODS: Body temperatures and arterial blood gases were measured in 48 patients during perioperative period. 24 patients had an amino acid mixture of 227 cal infused over 2 hours before anesthesia and 24 control patients received Hartman's solution. RESULTS: Amino acid infusion attenuated the development of hypothermia during the period from 60 min to 105 min after induction of anaesthesia compared to control group, however, did not prevent overall hypothermia throughout the study period. CONCLUSION: This result may indicate amino acid infusion before anesthesia can be an adjuvant to prevent intraoperative hypothermia.