Purpose : To consider and differentiate oedema fluid from other fluids in the performance of epidural block. Clinical features; A patient underwent placement of an epidural catheter for vaginal delivery of twins. Following a loss of resistance technique using air a small amount of fluid was aspirated through the needle and subsequently through the epidural catheter. The epidural block and delivery followed uneventfully. After delivery oedema fluid oozed from the puncture site for a number of days. Laboratory investigation revealed that this fluid was of oedematous origin. Bedside determination of alkaline pH by ComburlO Test M urine stick appeared to be a simple and useful test for distinguishing the oedema fluid from fluids of other possible sources. Conclusion: When performing an epidural blockade the retum of fluid may be due to oedematous fluid. Differentiation of the pH by a simple bedside test can aid in the differential diagnosis and prevent unnecessary additional attempts at needle repositioning.