AIMS AND OBJECTIVES: The aim of this prospective study was to examine whether preoperative face-to-face counselling about a child's fasting and active preoperative nutrition have an effect on thirst, hunger and postoperative oral intake in paediatric ambulatory tonsillectomy. Families, whose child was admitted for ambulatory tonsillectomy, participated in the study (n = 116; 58/58). BACKGROUND: Children undergoing tonsillectomy have difficulties in postoperative recovery and nutrition. However, former studies have shown that shorter preoperative fasting seems to promote postoperative well-being and promote the child's postoperative oral intake. DESIGN: A prospective, randomised intervention study. METHODS: The study groups were randomly allocated. The intervention group received the instructions through face-to-face counselling about the child's active preoperative nutrition, the control group received the instructions according to the current practice. The postoperative thirst and hunger were scored during the first postoperative hour and at two, four, eight and 24 hours postoperatively. The first scoring was performed by the nurse on a 0-10 scale. The rest of the estimations were made by the children using a visual analogue scale (VAS), by the parents using a 0-10 scale. RESULTS: In the intervention group, the VAS scores in thirst and hunger were low during the first 24 postoperative hours, whereas in the control group, they increased towards the following morning when the children in the control group, according to the children and the parents, were thirstier (p = 0.051, 0.005, respectively) and significantly hungrier (p = 0.042, 0.005) than those in the intervention group.RELEVANCE TO CLINICAL PRACTICE: Clinical practice should take the child's perioperative fasting into account in a more accurate way in preoperative counselling of the parents.