THE USE OF CONTINUOUS LUI~IBAlq EPIDURAL BLOCK for pain relief during the 1st and 2nd stages of labour was first described by Flowers, Hellman and Hingson in 1949.1 Today, some twenty years later, this technique is commonly used in Canada in the majority of the larger hospitals dealing with obstetrical cases. It has been in use at the Hamilton Civic Hospitals over the past five years, and a description of this has been given by Carton (1969). 2 Approximately 65 per cent of our patients now receive this form of pain relief in labour. It is essential to differentiate the pain of the first stage of labour, which is transmitted mainly by afferents which travel with the sympathetic nerves and enter the spinal cord between T-10 and L-1 segments, from the pain of the second stage which is relayed by somatic nerves (mainly s-2, 3 & 4), but also by L-1 and L-2 ( ilioninguinal and genito-femoral nerves ). Pain of the first stage can be relieved by relatively small volumes of local anaesthetic drugs (5-7 ee). The drug commonly used at the Hamilton Civic Hospitals is Liguoeaiue in concentration 0.5--1 per cent; thus producing block of these sympathetic "e" fibres. Pain of the, 2nd stage requires blocking of somatic nerves and therefore higher concentration (1 per cent 1.5 per cent Lignocaine) and larger volumes ( 10-15 ee) in order to achieve satisfactory perineal analgesia for episiotomy and forceps delivery. It is the custom in this institution to deliver patients routinely by episiotomy and forceps, and it has been observed that a block extending from mid-thigh to umbilicus is adequate for this. Recently, a new local anaesthetic called Bupivaeaine (LAC-43) has been introduced. This drug was synthesized by Af Ekerstam, Eguer, and Patterson a in 1957, and its clinical use described bv Widman 4 in 1964. Henn and Brattsand 5 gave this drug bv various routes in mice, guinea-pigs and rabbits and concluded that its acute toxicity was equivalent to that of Amethoeaine and four times that of Mepivacaine. In regional block (local, epidural, and caudal) they stated that Bupivaeaine and Amethocaine were approximately three times more potent than Mepivaeaine. It is the Hydrochloride of 1-n-butylq)L Piperidine-2-Carboxylie Aeid-2-6-dimethylanilide, being similar in structure to Mepivacaine, but differs from it in that a Methyl group in the piperidine ring has been replaced by a butyl group. This drug is still undergoing clinical trial in Canada, but has been used in Europe over the past 3 to 4 vears. The great virtue claimed for this local