This study compares the effectiveness of two drug combinations--(a) bupivacaine with adrenaline and (b) bupivacaine with adrenaline and pethidine--on operative and postoperative pain relief when administered by the caudal route in infants and children. A randomised controlled trial was conducted on fifty children below the age of twelve years: 25 children were randomly allocated to each group. Both groups had a significant period of analgesia in the postoperative period. None of the children in either group required parenteral analgesia. Though the group with pethidine had a longer duration of analgesia and sedation, the very high incidence of vomiting and delay in urination observed in this group would preclude the use of pethidine routinely. No respiratory depression was seen in either group.