A comparative trial between three different dosage regimens of bupivacaine administered by the caudal route, used for the prevention of postoperative pain in children undergoing elective inguinal herniotomy or ligation of patient processus vaginalis was undertaken. The regimens compared were bupivacaine 0.25% (1 ml/kg), bupivacaine 0.25% or 0.5%: (Age (years +2)/10 ml per dermatome to be blocked. This being calculated for inguinal surgery to be Age (years) + 2 ml. A linear analogue pain scale was used to evaluate pain, all three regimens being found to produce excellent analgesia, there being no significant difference between the pain scores of the three groups. Time to onset of analgesia, as indicated by changes in intraoperative heart rate in response to surgical stimulation were also similar in all groups. No evidence of postoperative motor weakness or disturbance of bladder function was found and there were no symptoms or signs attributable to local anaesthetic toxicity.