The efficacy of dexamethasone alone or in combination with a serotonergic antagonist to prevent nausea and vomiting in laparoscopic cholecystectomy is well established, but few data exist regarding its effects on perioperative cortisol and glucose levels. Fourteen non-diabetic subjects having elective laparoscopic choleycystectomy and standardised general anaesthesia were randomised to receive 8 mg of intravenous dexamethasone and tropisetron or tropisetron alone. Plasma cortisol and glucose were measured preinduction, at five and 24 hours postoperatively. There was no difference in plasma cortisol at five hours postoperatively in patients who received dexamethasone, but by 24 hours there was marked suppression compared to the control group (P < 0.005) to less than 5% of the preoperative value. There was a small but statistically significant elevation in blood glucose at 24 hours (P < 0.01) in the dexamethasone-treated group. In patients undergoing laparoscopic cholecystectomy, an anti-emetic dose of dexamethasone (8 mg) markedly suppresses plasma cortisol at 24 hours and causes a minor elevation in blood glucose.