Propofol (2,6 disopropylphenol) is a short-acting hypnotic agent, effective for the maintenance of anaesthesia when given intravenously as repeated bolus injections or as a continuous infusion. The present paper deals with the analysis of this drug in different parts of the blood. The results obtained by means of HPLC show that propofol not only variously bonds with plasma or solid blood elements, but also penetrates into the interior of blood cells.