Propofol is a short acting hypnotic agent and has many uses both in sedation and general anaesthesia. In sub-anaesthetic doses it has useful sedative and anxiolytic properties. It may be administered by continuous infusion or by Target Controlled Infusion (TCI) systems. The TCI infusion pump incorporates a pharmacokinetic model to calculate and deliver enough propofol to maintain a stable concentration of drug in a patient and maintain an optimum level of sedation. The anaesthetist administering the drug uses a TCI (target controlled infusion) pump which adjusts the rate of delivery according to a pharmacokinetic/pharmacodynamics model, of which there are several models which have been shown to be clinically effective. Keywords: propofol