After a rather long initial period fraught with difficulties, plasma exchange has become an adjunct to the treatment of numerous diseases, such as hyperviscosity syndrome, where it alleviates disease symptoms, hemophilia due to inhibitors to clotting factor VIII, thrombotic thrombocytopenic purpura, rapidly progressing and Goodpasture glomerulonephritis, myasthenia gravis and Guillain Barre syndrome. In addition, plateletpheresis has also grown from being a procedure of experimental clinical application to one of practical routine importance; at the Berne University Hospital, approximately 25% of all transfused platelets in 1986 were apheresis platelets, a proportion that elsewhere may reach 40%. Despite the successes so far obtained with apheresis, many aspects of this therapy remain to be reconsidered. Improvement of donor-recipient matching and of yield in plateletpheresis, better selection of replacement fluids, and increased donor and patient safety and comfort may further strengthen the value of apheresis in therapeutic protocols. This was the major background for the scientific program of the 4th Annual Meeting of the European Society for Hemapheresis that was assembled to shed light on those aspects of the apheresis field which are still unclear. A total of 31 lectures and 76 individual contributions were debated by 280 participants from Europe and overseas. The present essay is a review of the highlights of this meeting, the main lectures of which were published in Plasma Therapy and Transfusion Technology, vol. 7, 1986.