Surgical stress may cause neural, endocrine, metabolic and humoral responses depending on the severity of the procedure. In this study, we aimed to study the effect of the preoperatively given ascorbic acid (AA), which is an antioxidant, and its role in the biosynthesis of neuropituitary hormones on the surgical stress response. Twenty-two American Society of Anaesthesiologists I and II patients ageing between 18 and 40, who have no endocrine and metabolic disease, and undergoing abdominal operation for non-malignant diseases were allocated to the study. These non-premedicated patients were divided into two groups in random: Group I, etomidate group; and Group II, AA plus etomidate group. AA was given to patients in Group II 20 min before etomidate injection. After monitoring the patient, anaesthetic induction was applied by giving 0.3 mg/kg of etomidate, 2 mug/kg of fentanyl and 0.1 mg/kg of vecuronium. Anaesthesia was continued with 1-0.7% isoflurane and N2O/O-2 (67 and 37%, respectively). Tramadol was given for the management of post-operative analgesia. Blood samples were obtained from all patients before the operation and at second, sixth, twelfth and twenty-forth hours after the beginning of operation for cortisol, adrenocorticotropic hormone (ACTH), osteocalcin, insulin and blood glucose level analyses. There was no statistically significant difference in cortisol, osteocalcin, insulin and glucose levels in both groups, when compared to the control levels. Whereas, patients in Group II had higher levels of cortisol than the control group at sixth hour, which were in normal limits, and there was no decrease in osteocalcin concentration. ACTH level was increased at the second and sixth hours, which was statistically significant, but at twelfth and twenty-forth hours, they were close to control group levels. As a result, we conclude that AA given before anaesthesia achieved by etomidate is not sufficient for the prevention of surgical stress response and that AA induction before anaesthesia should be preferred, particularly for the prevention of decrease in osteocalcin levels.