The present invention relates to a process for purifying immunoglobulin G from a crude immunoglobulin-containing plasma protein fraction. Said process includes a number of steps of which the anion exchange chromatography and the cation exchange chromatography are preferably connected in series. An acetate buffer having a pH of about 5.0-6.0 and having a molarity of about 5-25 mM is preferably used throughout the purification process. The invention further comprises an immunoglobulin product which is obtainable by this process. The invention also relates to an immunoglobulin product which has a purity of more than 98%, has a content of IgG monomers and dimers of more than 98.5%, has a content of IgA less than 4 mg of IgA/l, and contains less than 0.5% polymers and aggregates. Said product does not comprise detergent, PEG or albumin as a stabilizer. The product is stable, virus-safe, liquid and ready for instant intravenous administration.