The present invention relates to a separation matrix comprised of porous particles to which antibody-binding protein ligands have been immobilized, wherein the ligand density is in the range of 5.0-10 mg/ml; the gel phase distribution coefficient of the particles expressed as Kav for a dextran of size 110 kDa is above 0.65 and the median particle diameter is between 65-84 μm. The carbohydrate material is preferably highly cross-linked agarose.