SEVERAL methods for the preparation1,2 or quantitative isolation3 of phosphatidylserine are now in existence. An investigation of some of the factors involved in the chromatography of phospholipids4,5 revealed the role of H+ ion exchange in the conversion of the salt form to the acidic form of phosphatidylserine on a silicic acid column. The recognition of this phenomenon, which was also indicated by experimental results published afterwards6, led to the development of a so-called silicic acid–‘Hyflo Super Gel’ column in the sodium form. These columns have been used successfully for the preparation of phosphatidylserine of high purity from ox-brain in conjunction with a shortened version of the method of Folch7 for the isolation of phosphatidylserine-rich fractions.