Abstract: Guest Editor's Introduction: Selective adsorption of target substances can be achieved based upon the application of physical and chemical interactions as well. Asahi Medical Co. developed 2 types of selective adsorbent columns, Immusorba PH‐350, and Immusorba TR‐350. These adsorbents consist of crosslinked polyvinyl alcohol gel beds with microporous structures for the base material, which immobilized a specific amino acid with hydrophobic property. Immusorba PH‐350 has phenylalanines as the ligand, which adsorbs the pathogenic substances such as immune complexes and anti‐DNA antibody. Tryptophan is immobilized in the Immusorba TR‐350, which adsorbs antiacetylcholine receptor antibodies. This paper describes the basic designs, adsorption characteristics, and summary of clinical applications of these adsorbents. This paper was printed in Therapeutic Apheresis, vol 2, page 185–192 (1998), and reprinted here with permission.Immusorba was reported by Yamazaki et al. to be the world's first practical immunoadsorbent in 1982. Since then, this immunoadsorbent has accumulated an abundance of clinical achievements. Immusorba has such unique functions that it is used in treating various diseases and holds possibilities for application to more diseases. Immusorba was designed as an artificial receptor for rheumatoid factor (RF) based on structural analysis of heat‐denaturated globulin. Subsequently, new substances that it can adsorb have been found as seen in reports on the adsorption performance of Immusorba to anti‐acetylcholine receptor antibodies (anti‐AChR Abs) and antiganglioside antibodies. Along with this, Immusorba has been used in treating a wide range of diseases. The greatest characteristic of Immusorba is that its adsorption capability is selective rather than specific, making it effective against a great number of diseases.