It has been suggested that children undergoing tonsillectomy would benefit from an intravenous infusion, to counteract the period of pre-operative fasting combined with the blood loss at operation. A prospective study of 50 children undergoing tonsillectomy was undertaken. The children were randomly allocated into two groups, one to receive an infusion and a control group. There were no significant differences between the two groups, although the children with an infusion had a longer mean post-operative stay. There would seem to be no role for routine intravenous fluid replacement in children undergoing uncomplicated tonsillectomy.