A study carried out on 44 patients undergoing laparoscopic cholecystectomy was started in order to evaluate if nitrous oxide is or not contraindicated. The patients were divided in two groups of 22 subjects receiving or not nitrous oxide in the anaesthetic mixture. All the patients received the same preanaesthetic medication (diazepam and atrophine), thiopental and fentanyl as induction drugs, vecuronium as muscle relaxant and isoflurane for maintenance of anaesthesia. Bowel distension, technical difficulty, incidence of postoperative nausea and vomiting were examined. Our conclusions were that nitrous oxide has no clinically deleterious effects during laparoscopic cholecystectomy.